Briggs Stratton

Briggs & Stratton

SERVICE MANUAL

BRIGGS & STRATTON BRIGGS & STRATTON CORPORATION Milwaukee, Wisconsin 53201

Model 19, 19D, 191000, 193000

No. Cyls.

200000

1 1

23,23A, 23C, 23D, 23100, 233000 243000 300000, 301000 302000 320000 325000 326000

Engines in this section are four-cycle, one cylinder horizontal crankshaft models. Crankshaft is supported at each end in bushing type main bearings which are an integral part of main bearing support plate or by ball bearings which are pressed onto crankshaft and fit into machined bores of main bearing support plates. Cylinder block and crankcase are a single cast iron casting. Connecting rod in all models rides directly on crankpin joumal and is splash lubricated by an oil dipper attached to connecting rod cap. Early models use a variety of magneto ignition systems with points and condenser either mounted externally or underneath flywheel. Late production models use Briggs & Stratton Magnetron breakerless ignition system. A float type carburetor is used on all models and a fuel pump is available as optional equipment for some models. Refer to BRIGGS & STRATTON ENGINE IDENTIFICATION INFORMATION section for engine identification and always give engine model and serial number when ordering parts or service material.

Bore

Stroke

Displacement

Power Rating

3 in. (76.2 mm) 3 in. (76,2 mm)

2.625 in. (66,675 mm) 2.875 in. (73.025 mm)

18.56 cu. in. (304.1 cc) 20.32 cu. in. (333 cc)

7.25 hp. (5.5 kW) 8hp. (6kW)

3 in. (76.2 mm) 3.0625 in. (77.79 mm)

3.25 in. (82.55 mm) 3,25 in. (82,55 mm)

22.97 cu. in (376.5 cc) 23.94 cu. in. (392.3 cc)

9 hp. (6.7 kW) 10 hp. (7.5 kW)

3,4375 in, (87.31 mm) 3,4375 in, (87.31 mm) 3.5625 in. (90.5 mm) 3.5625 in. (90.5 mm) 3.5625 in. (90.5 mm)

3,25 in. (82,55 mm) 3,25 in, (82.55 mm) 3.25 in. (82.55 mm) 3.25 in. (82,55 mm) 3,25 in. (82,55 mm)

30.16 cu. in. (494.2 cc) 30.16 cu. in, (494,2 cc) 32.4 cu. in. (531 cc) 32.4 cu. in. (531 cc) 32.4 cu. in. (531 cc)

12 hp. (9kW) 13 hp, (9.7 kW) 14 hp. (10.4 kW) 15 hp. (11.2 kW) 16 hp. (11.9 kW)

plug is Champion J8 or equivalent. To decrease radio interference use Champion XJ8 or equivalent spark plug. Electrode gap for all models is 0.030 inch (0.762 mm). CARBURETOR. All models are equipped With a two-piece float type carburetor. Refer to Fig, B30 for a crosssectional view of carburetor and location of mixture adjustment screws. For initial carburetor adjustment, open idle mixture screw 1 turn and main fuel mixture screw IV2 turns. Make final adjustment with engine at normal operating temperature and run-

ning. Place engine under load and adjust main fuel mixture screw for leanest mixture that will allow satisfactory acceleration and steady governor operation. Set engine idle mixture screw to obtain smoothest idle operation. As each adjustment affects the other, adjustment procedure may have to be repeated. To check float level for all models, invert carburetor body and float assembly. Refer to Fig. B34 for proper float level dimensions. Adjust by bending float lever tang that contacts inlet valve. Check carburetor for upper body warpage using a 0.002 inch (0.0508 mm)

-THttOTTLf VALVE

Fig. B30'-Cross-sectional view of typicai two-piece fioat type carburetor. Before separating upper and lower carburetor bodies, loosen packing nut and unscrew needle valve and pecking nut. Use speciai screwdriver, part number 19062 to remove nozzle.

PUtL IHLET

MAINTENANCE NCEOCE

SPARK PLUG. Recommended spark Illustrations courtesy of Briggs & Stratton Corp.

VALVE

273

Briggs & Stratton

GENERATOR check position of counterweight lever. Lever should be in a horizontal position with free end towards right. FUEL PUMP. A diaphragm type fued pump is available on some models as optional equipment. Refer to SERVICIMJ BRIGGS & STRATTON ACCESSORIES section for service information. Fig. B33 — Check carburetor upper body for warpage. If a 0.002 Inch (0.0S08 mm) feeier gage can be inserted between upper and iower bodies as shown, renew upper body.

tmn fAifC !/•' fPfi

V + 1" X-32

Fig. 83t — Typical SAS automatic choke unit in ''HOT" position.

feeler gage as shown in Fig. B33. If upper body is warped more than 0.002 inch (0.0508 mm) it should be renewed. AUTOMATIC CHOKE. A thermo

stat operated choke is used on some models. To adjust choke linkage, hold choke shaft so thermostat lever is free. At room temperature, stop screw in thermostat collar should be located midway between thermostat stops (Fig. B31 & B32). If not, loosen stop screw, adjust collar and tighten stop screw. Loosen set screw (S-Fig. B31) on thermostat lever. Slide lever on shaft to insure free movement of choke unit. Turn thermostat shaft clockwise until stop screw contacts thermostat stop. While holding shaft in this position, move shaft lever

Fig. B34~ Check carburetor float setting as shown. Bend tang if necessary to adjust fioat level.

until choke is open exactly Vs-inch (3.18 mm) and tighten lever set screw. Turn thermostat shaft counter-clockwise until stop screw contacts thermostat stop as shown in Fig. B32. Manually open choke valve until it stops against top of choke link opening. At this time choke should be open at least 3/32-inch (2.25 mm), but not more than 5/32-inch (4 mm). Hold choke valve in wide open position and

GOVERNOR. All models are equipped with a gear driven mechanical governor. Governor weight unit is enclosed within engine and is driven by camshaft gear. Refer to Fig. B62, Bm or B64 for appropriate exploded view of model being serviced. To adjust governor, loosen screv^ holding governor lever to governor crank (46-Fig. B62, B63 or B64). Push governor lever as far clockwise as it will go. Tighten screw holding governor lever to crank until it is snug, but not tight. Push governor lever as far counter-clockwise as it will go and tighten screw securely. Governor gear and weight unit can be removed when engine is disassembled. Remove governor lever, cotter pin and washer from outer end of governor crank. Slide crank out of bushing towards inside of engine. Governor gear and weight unit will then slide off of shaft. Shaft can be removed from crankcase if necessary. Renew bushing in crankcase for governor crank if bushing is worn and ream new bushing, after installation, to 0.2385-0.239 inch (6.06-6.07 mm). Refer to Figs. B35 through B38 for governor control and carburetor linkage hook-up and adjustments.

COUITCI CLOCniSC

Fig. B3S-Views showing method of connecting different remote governor controis. Moving controi iever wiii vary governor spring tension, thus varying engine governed speeds. For views showing remote throttle controis, refer to Fig. B36.

Fig. B32—Typical B^S automatic choke in "COLD'' position.

274

Illustrations courtesy of Briggs & Stratton Corp-

Briggs & Stratton

SERVICE MANUAL

Fig. B36-Views showing methods of connecting remote throttie controis. When controi iever is in high speed position, governor controis speed of engine and governed speed Is adjusted by turning thumb nut. Moving control lever to slow speed position moves carburetor throttie shaft stop to decrease engine speed.

Plunger should be renewed if worn to a length of 0.870 inch (22.098 mm) or less. Plunger bore diameter may be checked using B&S plunger bore gage, part number 19055. If gage enters plunger bore V4-inch (6.35 mm) or more, install service bushing, part number 23513. To install bushing, remove bearing support from engine, then ream bore using B&S reamer, part number 19056, drive bushing in flush with outer end of plunger bore with B&S driver, part number 19057 and use B&S reamer, part number 19058, to finish ream inside of bushing. When reinstalling flywheel, inspect the soft metal key and renew if damaged in any way. NOTE: Renew key with correct B&S part. DO NOT substitute a steel key.

IGNITION SYSTEM. Early models use a variety of magneto type ignition systems and late production models use Briggs & Stratton Magnetron ignition system. Refer to appropriate paragraph for model being serviced. MODEL 23C MAGNETO. Refer to Fig. B39 for exploded view of magneto used on 23C model engine. Condenser

SPEED ADI. NUTS

Fig. B37— View showing governor linkage, springs and levers properly instaiied on 243000, 300000, 301000, 302000, 320000, 325000 and 328000 series engines. Refer to Fig. B38 for remote control hook-up. Illustrations courtesy of Briggs & Stratton Corp.

After flywheel is installed and retaining nut tightened, check armature air gap and adjust as necessary to 0.022-0.026 inch (0.5588-0.6604 mm). MODELS 19, 23 & 23A AND SERIES 191000 & 231000 MAGNETO. Refer to Fig. B40 for exploded view of and breaker points are mounted on magneto used on these models. Condenser and breaker points are crankshaft bearing support plate (17) and are accessible after removing fly- mounted externally in a breaker box located on carburetor side of engine and wheel and magneto cover (7). Breaker point gap is 0.020 inch (0.508 are accessible after removing breaker mm) and condenser capacity is 0.18-0.24 box cover (18-Fig. B40). Breaker point gap is 0.020 inch (0.508 mfd. Breaker point plunger can be removed mm) and condenser capacity is 0.18-0.24 from bore in crankshaft bearing support mfd. When renewing breaker points, or if when breaker points are removed. oil leak is noted, breaker shaft oil seal (16) should be renewed. To renew points and/or seal, turn engine so breaker point gap is at maximum. Remove terminal and breaker spring screws and loosen breaker arm retaining nut (19) so it is flush with end of shaft (29). Tap loosened nut lightly to free breaker arm (21) from taper on shaft, then remove breaker arm, breaker plate (22), pivot (23), insulating plate (24) and eccentric (17). Pry oil seal out and press new oil seal in with metal side out. Place breaker plate on insulating plate with dowel on breaker plate entering hole in insulator. Then, install unit with edges of plates parallel with breaker box as shown in Fig. B41. Turn breaker shaft clockwise as far as possible and install breaker arm while holding shaft in this position. Breaker box can be removed without removing points or condenser. Refer to Fig. B42. Disassembly of unit is evident after removal from engine. To renew ignition coil, engine flywheel must be removed. Disconnect coil ground and primary wires and pull spark plug wire from hole in back plate. Fig. B38—Remote governor control installation on 243000, 300000, 301000, 302000, 320000, Disengage clips (8-Fig. B40) retaining coil core (9) to armature (14) and push 32S0O0 and 328000 series engines. 275

Briggs & Stratton

GENERATOR

core from coil. Insert core in new coil with rounded side of core towards spark plug wire. Place coil and core on armature with retainer (7) between coil

and armature. Reinstall core retaining clips, connect coil ground and primary wires and insert spark plug wire through hole in back plate.

15 16

Two types of magnetic rotors have been used. Refer to Fig. B43 for view of rotor retained by set screw and to Fig. B44 for rotor retained by clamp ring. If rotor is as shown in Fig. B44, refer to Fig. B45 when installing rotor on crankshaft. If armature coil has been loosened or removed, rotor timing must be read^

«— PARALLEL

1 2 3

7

11

18 17

Fig. B39-Expioded view of magneto ignition system used on 23C modei engines. Breaker points and condenser are mounted on bearing support (i7) and are endosed by cover (7) and fiywheei. Points are actuated by piunger (i3) which rides against breaker cam machined on engine crankshaft. 1. 2. 3. 4. 5. 6.

Flywheel nut Nut retainer Starter pulley Blower housing Flywheel key Flywheel

7. 8. 9. 10. 11. 12.

Breaker cover Spark plug wire Breaker point base Breaker point arm Breaker spring Coil & armature

13. 14. 15. 16. 17. 18.

Plunger Armature support Back plate Shim gasket Bearing supfx)rt Condenser

Fig. B4i — When instaiiing breaker points on 79, 23 and 23A modeis and T9T000 and 23i000 series engines, be sure dowei on breaker point base enters hoie in insuiator. Piace sides of base and insuiating piate paraiiei with edge of breaker box.

9 . 10

Fig, B42- To remove breaker box on f9, 23 and 23A modeis and i9i000 and 231000 series engines it is not necessary to remove points and condenser as unit may be removed as an assembly.

SET SCREW

Fig, B40-Exploded view of magneto ignition system used on 19,23 and 23A models and i9i000 and 231000 series engines. Fiywheei is not keyed to crankshaft and may be instailed in any position; however, on crank start modeis, fiywheei shouid be instaiied as shown in Fig. B47. Breaker arm (2i) is mounted on shaft (29) which Is actuated by a csm on engine cam gear. See Fig. B48. Two different methods of attaching magneto rotor (5) to engine crankshaft have been used. Refer to Figs, B43 and B44, 1. 2. 3. 4. 5. 6. 7.

Starter pulley Blower housing Flywheel Rotor clamp Magneto rotor Ignition coil Coil clip

276

9. 10. U. 12. 13. 14. 15.

Coil core Back plate Bearing support Shim gasket Rotor key Armature Primary coil knid

16. 17. 18. 1<). 20. 21. 22.

Shaft seal Eccentric Breaker IK)X c{)ver Nut Washer Breaker ^K)int arm Breaker iH>int Inise

23. 24. 25. 26. 27. 28. 29.

Pivot Insulator Condenser Seal retainer Breaker IKIX Gasket Shaft

ROTOR KEY

Fig. B43 — On some modeis, magneto rotor ist • fastened to crankshaft by a S9t screw which enters hoie in shaft. Set screw is iocked inplace by a second screw. Refer to Fig. B44 aiso. Illustrations courtesy of Briggs & Stratton Corp.

Briggs & Stratton

SERVICE MANUAL \CLAMP WITH CLAMP SCREW . ANO LOCK WASHER

KEY

Fig. B47- On f 9,23 and 23A modeis and i9iOOO and 23i000 series engines equipped with crank starter, mount flywheel with pin in position shown with armature timing marks aligned,

Ffg. B44-View showing magneto rotor fastened to crankshaft with ciamp. Make certain spUt in mounting holes so arrow is aligned with clamp is t>etween two slots in rotor as shown and check ciearance between rotor and shoulder appropriate engine model number on rotor. Tighten armature mounting on crankshaft as shown In Fig. 845.

justed. With point gap adjusted to 0.020 inch (0.508 mm), connect a static timing light from breaker point terminal to ground (coil primary wire must be disconnected) and turn engine in normal direction of rotation until light goes on. Then, turn engine very slowly in same direction until light just goes out (breaker points start to open). At this time, engine model number on magneto rotor should be aligned with arrow on armature as shown in Fig. B46. If not, loosen armature core retaining cap screws and turn armature in slotted FEELER CAUCE

lELER CAUCE

screws. To install flywheel on models with crank starter, place flywheel on crankshaft as shown in Fig. B47 with magneto timing marks aligned as in previous paragraph. On models not having a crank starter, flywheel may be installed in any position. Magneto breaker points are actuated by a cam on a centrifugal weight mounted on engine camshaft (Fig. B48). When engine is being overhauled, or cam gear is removed, check action of advance spring and centrifugal weight unit by holding cam gear in position shown and pressing weight down. When weight is released, spring should return weight to its original position. If weight does not return to its original position, check weight for binding and renew spring. MODELS 19D & 23D MAGNETO. Refer to Fig. B49 for exploded view of magneto system.

Fig. B48-Check timing advance weight and spring on 19,23 and23A models and i9i000 and 23i000 series engines. Refer to text.

Condenser and breaker points are mounted externally in a breaker box located on carburetor side of engine and are accessible after removing cover (8-Fig, B49). Breaker point gap is 0.020 inch (0.508 mm) and condenser capacity is 0.18-0.24 mfd. Installation of new breaker points is made easier by turning engine so points are open to their widest gap before removing old points. For method of adjusting breaker point gap, refer to Fig. B50. NOTE: When installing points, apply Permatex or equivalent sealer to retaining screw threads to prevent engine oii from leaking into breaicer box.

U Fig, B45-Modeis having magneto rotor clamped to crankshaft, position rotor 0,025 inch (0.635 mm) from shouider on shaft, then tighten clamping screw.

i 1 2

A

15

16

17

A 3

13

:•

8 9 10 il 12 Fig. B49-Exploded view of magneto ignition system used on I9D and 23D models. Magneto rotor (flywheei) to armature timing is adjustabie as shown in Figs. B51 and B52. Adjust breaker points as in Fig. B50. Fig. B46-With engine turned so breaker points are just starting to open, align model number iine on rotor with arrow on armature by rotating armature in slotted mounting holes. Illustrations courtesy of Briggs & Stratton Corp.

, 1. 2. 3. 4. a 6.

^ ^ , Flywhee nut Nutj^tainer Starter pulley Blower housing ^^ l ^ lY*""^ Flywheel key

7. g. 9. 10. n. ^2. 13.

Flywheel Breaker box cover Gasket Condenser Breaker points Breaker spring Lock nut

14. Coil & armature assy. 15. Armature mounting bracket 16. Back plate 17. Bearing support 18. Shim gasket

277

GENERATOR

Briggs & Stratton Breaker points are actuated by a plunger that rides against breaker cam on engine cam gear. Plunger and plunger bushing in crankcase are renewable after removing cam gear and breaker points. Magneto armature and ignition coil are mounted outside engine flywheel. Adjust armature air gap to 0.022-0.026 inch (0.5588-0.6604 mm). If flywheel has been removed, magneto edge gap (armature timing) must be adjusted. With point gap adjusted to 0.020 inch (0.508 mm) and flywheel loosely installed on crankshaft, install flywheel key leaving retaining cap screw loose. Disconnect magneto primary wire and connect test light across breaker points. Turn flywheel in clockwise direction until breaker points just start to open (timing light goes out). Now, while making sure engine crankshaft does not turn, turn flywheel back slightly in counter-clockwise direction so edge of flywheel insert lines up with edge of armature as shown in Fig. B53. Tighten flywheel key screw, then tighten flywheel retaining nut to 110-118 ft.-lbs, (149-160 N-m) torque for 19D model and to 138-150 ft.-lbs. (187-203 N-m) torque on 23D model. Readjust armature air gap as necessary. SERIES 193000, 200000, 233000, 243000, 300000, 301000, 302000, 320000, 325000 & 326000 MAGNETO. Refer to Fig. 54 for exploded view of magneto system. Condenser and breaker points are mounted externally in a breaker box located on carburetor side of engine and are accessible after removing cover (8-Fig. B54). Breaker point gap is 0.020 inch (0.508 mm) and condenser capacity is 0,18-0.24 mfd. Installation of new breaker points is made easier by turning engine so points TURN BREAKER POINT SCREW CLCXKWISE TO INCREASE GAP

FLYWHEEL INSERT

Fig. B5i-0n i9D and 23p modeis, magneto timing is adjusted by repositioning fiywheel on crankshaft, Flywheei is then iocked into proper position by tightening key screw and flywheel retaining nut. Refer aiso to Figs. B52 and B53.

Fig. B52- Turning engine in normai direction of rotation with flywheel and flywheei key ioose. Turn engine siowiy untii breaker points are just starting to open. Refer to text and Figs. B51 and B5X

Fig. B53-Turn fiywheei counter-clockwise on crankshaft until edge of flywheei insert is aiigned with edge of armature as shown in insert. Then, tighten fiywheei key screw and retaining nut.

WASHER

,020" GAP

CONDENSER

Fig. B50- On aii modeis equipped with this type of breaker points, ioosen iock nut and turn adjusting screw to obtain 0,020 inch (0.508 mm) gap.

278

6

8 9 10 11 12

Fig, B54-Expioded view of i93000, 200000, 233iHiO and 243000 series magneto ignition system. Magneto used on 300000,301000, 302000, 320000, i25000 and 326000 series is simiiar. Position of armature is adjustabie to time armature with magnsto rotor (flywheel) by moving armature mounting bracket (15) on slotted mounting holeti. Refer to text and Figs. 855 and B56, 1. 2. 3. 4. 6. 7.

Flywheel nut Nut retainer Starter pulley Blower housing Flywheel key Flywheel

8. 9. 10. 11. 12. 13.

Breaker box cover Gasket Condenser Breaker points Breaker spring Lock nut

14. Coil & armature assy. 15. Armature mounting bracket 16. Back plate 17. Bearing support 18. Shim gasket

Illustrations courtesy of Briggs & Stratton Coip.

SERVICE MANUAL

Briggs & Stratton ARMATURE Fig. B57~ After mounting bracket is properly instaiied (Fig. B56k Install armature and coii assembiy so there is a 0.010-0.014 inch (0.254-0.35S6 mm} air gap between armature and fiywheei.

MOUNTING BRACKET

.010" - .014" AIR GAP

ALIGNMENT ARROWS Fig. BBS-On 193000, 200000, 233000, 243000, 300000, 301000, 302000, 320000, 325000 and 32$000 series, time magneto by aiigning armature core support so arrow on support is aiigned with arrow on flywheel when breaker points are just starting to open. Refer to text for procedure.

are open to their widest gap before removing old points. For method of adjusting breaker point gap, refer to Fig. B50. NOTE: When installing points, appiy Permatex or equivaient sealer to retaining screw threads to prevent engine oii from ieaking into breaicer box.

Breaker points are actuated by a plunger that rides against breaker cam on engine cam gear. Plunger (43-Fig. B62) and plunger bushing (PB) are renewable after removing engine cam gear and breaker points. On 300000, 301000, 302000, 320000, 325000 and 326000 series engines breaker plunger and plunger bushing are similar to those shown in Fig. B62. Magneto armature and ignition coil are mounted outside engine flywheel. Adjust armature air gap to 0.010-0.014 inch (0.254-0.3556 mm). If flywheel has been removed, magneto edge gap (armature timing) must be adjusted. With point gap ad-

justed to 0.020 inch (0.508 mm) and armature ignition coil assembly removed from bracket connect a test light across breaker points. Disconnect coil primary wire and slowly turn flywheel in a clockwise direction until light just goes out (breaker points start to open). At this time, arrow on flywheel should be exactly aligned with arrow on armature mounting bracket (Fig. B55). If not, mark position of bracket, remove flywheel and shift bracket on slotted mounting holes (Fig. B56) to bring arrows into alignment. Reinstall flywheel, make certain arrows are aligned and tighten flywheel nut to 110-118 ft.-lbs. (149-160 N-m) torque on 193000 and 200000 series engines and 138-150 ft.-lbs. (187-203 N-m) torque on all remaining models. Readjust armature air gap as necessary. MAGNETRON IGNITION. Magnetron ignition is a self-contained breakerless ignition system. Flywheel does not need to be removed except to change timing by moving armature bracket or to service crankshaft key or keyway.

To check spark, remove spark plug and connect spark plug cable to B&S tester, part number 19051 and ground remaining tester lead to engine cylinder head. Spin engine at 350 rpm or more. If spark jumps the 0.166 inch (4.2 mm) tester gap, system is functioning properly. To remove armature and Magnetron module, remove flywheel shroud and armature retaining screws. Use a 3/16-inch diameter pin punch to release stop switch wire from module. To remove module, unsolder wires, push module retainer away from laminations and push module off. See Fig. B57A. Resolder wires for reinstallation and use Permatex or equivalent gasket sealer to hold ground wires in position. To set timing for gasoline fuel operation, install armature bracket so mounting screws are centered in slots (Fig. B57B). To set timing for kerosene fuel operation, install armature bracket as far to left as possible (Fig. B57B). Adjust a r m a t u r e air gap to 0.010-0.014 inch (0.25-0.36 mm).

ARMATURE MOUNTING BRACKET

Fig. B57A-Wires must be unsoidered to remove Magnetron module.

MOUNTING SCREWS Fig. BS$~Vi0w with fiywheei removed on 193000, 200000, 233000, 243000, 300000, 301000, 302000, 320000, 325000 and 326000 series engines. Magneto Is timed by shifting armature mounting bracket on siotted mounting holes. Refer to Fig. B55 aiso. Illustrations courtesy of Briggs & Stratton Corp.

279

Briggs & Stratton

GENERATOR

IGNITION ARMATURE WITH MAGNETRON" MOOULE ASSEMBLY

^ CAM GEAR SIDE FLAT

MOUNTING SCREWS "CENTERED" IGNITION ARMATURE WITH "MAGNETRON" MOOULE ASSEMBLY

Fig. B57B-Upper view shows position of armature bracket for gasoline fuels and iower view shows position of armature bracket for kerosene fuels for correct ignition timing.

REPAIRS CYLINDER HEAD. When removing cylinder head note location from which different cap screws are removed as they must be reinstalled in their original positions. Always use a new gasket when reinstalling cylinder head. Do not use sealer on gasket. Lubricate cylinder head bolt threads with graphite grease, install in correct locations and tighten in several even steps in sequence shown in Fig. B58 according to type head used. Tighten cap screws to 190 in.-lbs. (22 N*m) torque. Start and run engine until normal operating temperature is reached, stop engine and retighten head bolts as outlined.

Fig. B58-View of two different cylinder heads used. Tighten cylinder head cap screws in sequence shown to 190 in.lbs. (22 N-m) torque. Refer to text for tightening procedure.

280

It is recommended carbon and leaci deposits be removed at 100 to 300 hour intervals, or whenever cylinder head is removed. CONNECTING ROD. Connecting rod and piston are removed from cylindei:* head end of block as an assembly. Aluminum alloy connecting rod rides directly on induction hardened crankshaft crankpin journal. Rod should b
MOUNTING SCREWS TO FAR LEFT"

LUBRICATION. All models are splash lubricated by an oil dipper attached to connecting rod. Oils approved by manufacturer must meet requirements of API service classification SE or SF. Use SAE lOW-40 oil for temperatures above 20*^ F (-7° C) and SAE 5W-30 oil for temperatures below 20° F (-7° C). Check oil level at five hour intervals and maintain at bottom edge of filler plug. DO NOT overfill. Recommended oil change interval for all models is every 25 hours of normal operation. Crankcase oil capacity for 18.56 and 20.32 cubic inch models is 3 pints (1.4 L) and crankcase oil capacity for all remaining models is 4 pints (1.9 L).

Fig. B59—Drawing of iower end of connecting rod showing ciearance fiat and assembly marks.

REJECT SIZES FOR CONNECTING ROD Crankpin Model bore Pin bore* 19, 19D 190000 1.001 in. 0.674 in. (25.43 mm) (17.12 mm) 200000 1.127 in. 0.674 in. (28.63 mm) (17.12 mm) 23, 23A, 23C, 23D, 230000 1.189 in. 0.736 in. (30.20 mm) (18.69 mm) 240000 1.314 in. 0.674 in. (33.38 mm) (17.12 mm) 300000, 320000

1.314 in. 0.802 in. (33.38 mm) (20.37 mm) *Piston pins of 0.005 inch (0.127 mm) oversize are available for service. Piston pin bore in rod can be reamed to this size if crankpin Jbore is within specification. Connecting rod running clearance to crankpin is 0.0015-0.0045 inch (0.03810.1143 mm) and piston pin to rod pin bore clearance is 0.0005-0.0015 inch (0.0127-0.0381 mm). On 300000, 301000, 302000, 320000, 325000 or 326000 series engines, notch on top of piston and letter "F" on side of piston must be on the same side as assembly marks on connecting rod Illustrations courtesy of Briggs & Stratton Corp.

SERVICE MANUAL

Briggs & Stratton 23, 23A, 23C, 23D, 231000,233000

MOTCH

0,736 in, (18.69 mm)

300000, 301000, 302000, 320000, 325000,326000 . . . 0.801 in. (20.35 mm) Renew piston pin if pin is 0.0005 inch (0.0127 mm) out-of-round or if pin is worn to, or below, rejection diameter shown in chart. END PLAY

.002"-.008"

Fig. B61 — Crankshaft end play can be checked as shown on models with main bearings which are an integrai part of bearing support plates. ASSEMBLY MARKS

FLYWHEEL SIDE

Fig. B60-On 300000, 301000, 302000, 320000, 325000 and 326000 series, assembie piston to connecting rod with notch and stamped ietter "F" on piston to same side as assembiy marks on rod. Install assembiy In cylinder with assembly marks to fiywheei side of crankcase.

(Fig. B60). Install assembly in cylinder with assembly marks to flywheel side of crankcase. On all remaining models connecting rod position in crankcase is determined by clearance flat on rod as shown in Fig. B59. Assemble cap to rod by matching assembly marks. Tighten connecting rod cap screws on all models to 190 in.-lbs. (22 N-m) torque. 19. 20. 21. 22. 23. 24. 25. 26. 27.

PISTON, PIN AND RINGS. Aluminum alloy piston has two compression and one oil control ring and piston should be renewed if top ring side clearance in groove exceeds 0.007 inch (0.178 mm) or if piston is visibly scored or damaged. Piston should also be renewed or pin bore reamed for 0.005 inch (0.127 mm) oversize pin if pin bore is worn to, or greater than rejection diameter shown in chart. PISTON PIN BORE REJECTION SIZES Model Pin bore 19, 19D, 191000, 193000, 200000,243000 0.673 in. (17.09 mm)

PISTON PIN REJECTION SIZES Model Pin diameter 19, 19D, 191000, 193000, 200000,243000 0.671 in. (17.04 mm) 23, 23A, 23C, 23D,

231000, 233000 300000, 301,000, 302,000, 320000, 325000, 326000

0.734 in. (18.64 m m ) 0.799 in. (20,30 m m )

Ring end gap should be 0.0100.025 inch (0,245-0,635 mm) and compression ring should be renewed if end gap is greater than 0.030 inch (0.75 mm). Oil control ring should be renewed if end gap is greater than 0,035 inch (0.90 mm). Pistons used in 300000, 301000, 302000, 320000, 325000 and 326000 series engines have a notch and a letter "F" stamped in piston (Fig. B60) which

Spark plug Cylinder head Gasket Breather tube Breather Main bearing plate

21 20

19

Gasket

Engine crankcase & cylinder block 28. Governor shaft 29. Governor gear & weight unit 30. Camshaft 31. Cam gear 32. Tappets 33. Camshaft plug 34. Engine base 35. Gasket 36. Valves 37. Valve spring washers 38. Valve springs 39. Spring retainers or "Roto-Caps" 40. Keepers 41. Gasket 42. Tappet chamber cover 43. Breaker point plunger 44. Governor control lever 45. Governor spring 46. Governor crank 47. Governor control rod 48. Governor link 49. Governor lever 50. Output drive key 51. Crankshaft 52. Ball bearings (on models so equipped) 53. Oil dipper 54. Rod bolt lock 55. Connecting rod 56. Piston pin retaining rings 57. Piston pin 58. Piston 59. Piston rings

47

Fig. B62—Exploded view of typical 19D, 23D, 193000, 2(H>000, 233000 and 243000 engines. Breaker piunger bushing (PB) and governor crank bushing (GB} in engine crankcase (27) are renewable. Breaker piunger (43) rides against a lobe on cam gear (31),

Illustrations courtesy of Briggs & Stratton Corp.

281

GENERATOR

Briggs & Stratton must face flywheel side of engine after installation. Pistons and rings are available in a variety of oversizes as well as standard.

NOTE: A

chrome

piston

ring

set

is

availabie for siightiy worn standard bore cylinders. No honing or cyiinder degiazing is required for these rings. Cyiinder bore can be a maximum of 0.005 inch (0.127

CYLINDER. Standard cylinder bore diameters are listed in following chart. STANDARD CYLINDER B O R E SIZES Model Standard bore 19, 19D, 191000, 193000, 23, 23A, 230, 23D, 200000 231000, 233000 2.999-3.000 in. (76.18-76.23 m m ) 243000 3.0615-3.0625 in. (76.79-76.82 m m ) 300000, 301000, 302000 3.4365-3.4375 in. (87.287-87.313 m m ) 320000, 325000, 326000 3.5615-3.5625 in. (90.462-90.488 m m ) If cylinder is worn 0.003 inch (0.076 mm) or more, or out-of-round 0.0025 inch (0.0635 mm) or more, it should be resized to nearest oversize for which piston and rings are available.

new bearings are loose on journals. Bearings should be a press fit.

mm) oversize when using chrome rings.

CRANKSHAFT AND MAIN BEARINGS. Crankshaft may be supported at each end in main bearings which are an integral part of crankcase and sump or ball bearing mains which are a press fit on crankshaft and fit into machined bores in main bearing support plates. Crankshaft for models with main bearings as an integral part of main bearing support plates should be renewed or reground if journals are out-ofround 0.0007 inch (0.0178 mm) or more or if main bearing journals are worn to a diameter of 1,179 inch (29.95 mm) or less for 19, 19D models and 191000, 193000 and 200000 series engines or 1.3759 inch (34.95 mm) or less for 23, 23A, 23C, 23D models and 231000 and 233000 series engines. Crankshaft for models with ball bearing main bearings should be renewed if

21 20 23

19

Crankshaft for all models should be renewed or reground if connecting rod crankpin journal diameter is worn to, or beyond crankshaft rejection specifications as listed in following chart. CRANKSHAFT REJECTION SIZES Model Crankpin journal 19,19D, 190000,193000 0.996 in. (25.30 m m ) 200000 1.122 in. (28.5 m m ) 23, 23A, 23C, 23D, 230000 .... 1.184 in. (30.07 m m ) 243000, 300000, 301000, 302000, 320000, 325000, 326000 1.309 in. (33.25 m m ) Connecting rod is available for crankshaft which has had connecting rod crankpin journal reground to 0.020 inch (0.508 mm) undersize. Crankshaft main bearing support plates should be renewed if integral type

36

24

48

30 Fig. B63-^xpioded view of typicai modei 19, 23, 23A, 191000 and 231000 engines equipped with "Magna-Matic" ignition system; note ignition advance weight (A W). Refer to Fig. B40 for ignition system. Advance weight Spark plu^ Air baffle Cylinder head HeJwJ ^Lsket Breather tulK> Breather Hearing plate (plain tuishin^) ^5H. Bearing plate (\v.i\\ In-urin^) AW. 19. 20. 21. 22. 23. 24. 25.

282

2H. Cuisket 27. F^n^ne ixankca.^' & cylin(ier l)l(H'k 28. (fovernor shaft 21 >. (Governor ^ear & weight unit 3(», Camshaft 31. Cum ^ear 32. TapfH'ts 33. ('amshaft plu^

Knj^ne base Giwket Valves Valve spring; washers 38. Valve springes 39. S|irinjj retainers or "Roto-('aps" 40. KeefHTS 41. (IjLsket 34. 35. 3fi. 37.

42. TapjH't chamUr cov er 44. Cio\ 'ernor control lev 45. (K)\ erntvr spring; 4(i. (tO\ ernor crank 47. (rt)\ ernor control rcMi

48. (IO^ iTnor link 49. ()o\ •ernor lever

50. O u t p u t drive ke> 51. Crankshaft 52. Ball U'arin^rs (on nKMk'ls so e(iiiip( 53. Oil (iipjKT 54. KtMl lH)lt l(K-k 55. (^inntH'tinjj nxl 5(i. Ri'Uiininj; rinp* 57. I*isU)n pin 58. Piston 51>. F^iston rinjrs

Illustrations courtesy of Briggs & Stratton Corp.

SERVICE MANUAL

Briggs & Stratton

36 35

54 53

34

33

42

Fig. B64 - Expioded view of typical 300000, 30i000, 302000,320000, 325000 and 326000 engines. Balance weights, ball bearings and cover assemblies (2 and Z4) are serviced only as assemblies. 23. Gasket 1. Oil seal 12. Spring caps 24. Cover & balance assy. 46. (Governor crank assy. 35. Key 2. Cover & balance assy, 13. Valve springs (nriagneto end) 36. Ball bearing 47. Gasket (pto end) 14. Spring retainer or 25. Oil se^ 37. Drive gear bolt 48. Engine base 3. (iasket rotator 26. Retaining rings 38. Belleville washer 49. Valve lifters 4. "E" ring 15. Keepers 27. Piston pin 39. Govemor control 50. Govemor gear & 5. Idler gear 16. Breather assy. 28. Piston rings lever weight unit 6. Bearing support plate 17. Breather tube 29. Piston 40. Bearing support plate 51. Govemor shaft 7. Cylinder block 18. Idler gear 30. Connecting rod 41. Shim 52. Cam gear 8. Head gasket 19. "E" ring 31. Oil dipper 42. Control rod 53. Camshaft 9. Cylinder head 20. Shim 32. Rod bolt lock 43. Link 54. Balancer drive gear 10. Spark plug 21. Cam bearing 33. Ball bearing 44. Governor lever 55. Belleville washer 11. Valves 22. Balancer drive gear 34. Crankshaft 45. Govemor springs 56. Drive gear bolt

main bearing bores are 0.0007 inch (0.0178 mm) or more out-of-round or if bearing bore diameter is 1.185 inches (30.1 mm) or more for 19,19D models or 191000, 193000 and 200000 series engines, 1.382 inches (34.1 mm) or more for 23, 23A, 23C, 23D models or 243000, 300000, 301000, 302000,320000, 325000 and 326000 series engines. No service bushings for main bearings are available. Ball bearing mains are a press fit on crankshaft and must be removed by pressing crankshaft out of bearing. Renew ball bearing if worn or rough. Expand new bearing by heating in oil and install on crankshaft with shield side towards crankpin journal. Crankshaft end play should be 0.002-0.008 inch (0.0508-0.2032 mm) and is adjusted by varying thickness of gaskets between flywheel main bearing support plate and crankcase. Gaskets are available in a variety of thicknesses. When reinstalling crankshaft, make certain timing marks are aligned (Fig. B66 or B67). CAM GEAR AND CAMSHAFT. On 19, 19D, 23, 23A, 23C, 23D models or llustrations courtesy of Briggs & Stratton Corp.

191000, 193000, 200000, 233000 and 243000 series engines timing gear and camshaft lobes are cast as an integral part and are referred to as a "cam gear". Cam gear turns on a stationary shaft referred to as a "camshaft". Reject camshaft if it is worn to, or less than, a diameter of 0.4968 inch (12.62 mm). On all remaining models cam gear and lobes are an integral part referred to as a "cam gear". Camshaft (53-Fig. B64) rotates with cam gear (52). Camshaft rides in a bearing in cylinder block on pto end of engine and journal on camgear rides in renewable cam bearing (21)

A Fig, B6S — Synchro-Balance weights rotate in opposite direction of crankshaft counterweights on 300000, 30i000, 302000, 320000, 325000 and 326000 series engines.

on magneto end of engine. Renew camshaft if worn to 0.6145 inch (15.6 mm) or less and renew cam gear (52) if journal diameter is 0.8105 inch (20.6 mm) or less or if lobes are worn to a diameter of 1.184 inches (30.1 mm) or less for 300000, 301000 and 302000 series engines or 1.215 inches (30.9 mm) or less for 320000,325000 and 326000 series engines. When installing cam gear in 300000, 301000, 302000, 320000, 325000 and 326000 series engines, cam gear end play should be 0.002-0.008 inch (0.0508-0.2032 mm) and is controlled by

L

B C

283

GENERATOR

Briggs & Stratton using different thickness shims (20) between cam gear bearing (21) and crankcase. Shims are available in a variety of thicknesses. Tighten cam gear bearing cap screws to 85 in.-lbs. (10 N*m) torque. On models with "Magna-Matic" ignition system, cam gear is equipped with an ignition advance weight (AW-Fig. B63). A tang on advance weight contacts breaker shaft lever (29-Fig. B40) each camshaft revolution. On all other models, breaker plunger rides against a lobe on cam gear. On models with "Easy-Spin" starting intake cam lobe is machined to hold intake valve slightly open during part of compression stroke, thereby relieving compression and making engine easier to start due to increased cranking speed. NOTE: To check compression on models with "Easy-Spin" starting, engine must be turned bacicwards.

"Easy-Spin" cam gears can be identified by two holes drilled in web of gear. If part number of older cam gear and "Easy-Spin" cam gear are the same except for an "E" following new part number, gears are interchangeable. On all models, align timing marks on crankshaft gear and cam gear when reassembling engine. GOVERNOR WEIGHT UNIT. Tangs on governor weights should be square and smooth and weights should operate freely. If not, renew gear and weight assembly (29-Figs. B62 and B63) or (50-Fig. B64). Renew governor shaft if worn or scored. GOVERNOR CRANK. With governor weight and gear unit removed,

AND BELLEVILLE WASHER TORQUE 700 IN.-LBV

ing factory or field installed guide bushings so new bushing, part number 231218 may be installed. Valve tappet gap (cold) for 19, 19D models or 191000, 193000 and 200000 series engines is 0.007-0.009 inch (0.18-0.23 mm) for intake valves and 0.014-0.016 inch (0.36-0.41 mm) for exhaust valves. Valve tappet gap (cold) for all other models is 0.007-0.009 inch (0.18-0.23 mm) for intake valves and 0.17-0.19 inch (0.43-0.48 mm) for exhaust valves. To adjust valves, piston must be at "top dead center" on compression stroke. Grind end of valve stem off squarely to obtain clearance. V S ^ I V E CEAR \ \

IDLER GEAR

Fig, B67— View showing balancer drive gear on pto end of crankshaft being timed. With piston at TDC, insert 1/4-inch (6,35 mm) rod through timing hoie in gear and into iocating hoie in crankshaft bearing support piate.

remove and inspect governor crank; renew if worn, (governor crank should be free fit in bushing in engine crankcase with minimum bushing to crank clearance. Renew bushing if new crank fits loosely. Bushing should be finish reamed to 0.2385-0.239 inch (6.0579-6.0706 mm) after installation. VALVE SYSTEM. All models are equipped with renewable exhaust valve seat inserts and intake valve seats are machined directly into cylinder block. Seats are ground at a 45° angle and seat width should be 3/64 to 1/16-inch (1.2 to 1.6 mm). Service exhaust and intake valve seat inserts are available and are installed using special tools available from Briggs & Stratton. Valve face is ground at a 45° angle and valve should be renewed if margin is 1/64-inch (0.4 mm) or less after refacing. Valve guides should be checked for wear using valve guide gage number 19151. If gage enters valve guide 5/16-inch (7.9 mm) or more, guides should be reamed using reamer number 19183 and bushing number 19192 should be installed. Briggs & Stratton also had a tool kit, part number 19232, available for remov-

SYNCHRO-BALANCER. 300000, 301000, 302000, 320000, 325000 and 326000 series engines are equipped with rotating balance weights at each end of crankshaft. Balancers are geared to rotate in opposite direction of crankshaft counterweights (Fig. B6Ei). Balance weights, ball bearings and covers (2 and 24 - Fig. B64) are serviced as assemblies only. Balancers are driven from idler geai-s (5 and 18) which are driven by gears (22 and 54). Drive gears (22 and 54) are bolted to camshaft. To time balancers, first remove cover and balancer assemblies (2 and 24). Position piston at TDC. Loosen bolts (37 and 56) until drive gears will rotate on cam gear and camshaft. Insert a V4-inch (6.35 mm) rod through timing hole in each drive gear and into locating holes in main bearing support plates as shown in Figs. B66 and B67. With piston at TDC and V4-inc h (6.35 mm) rods in place, tighten dri\^e gear bolts to a torque of 200 in.-lbs. (23 N-m). Remove V4-inch (6.35 mm) rods. Remove timing hole screws (Fig. B63) and insert Vs-inch (3.18 mm) rods through timing holes and into hole in balance weights. Then, with piston at TDC, carefully slide cover assemblies into position. Tighten cap screws in pto end cover to 200 in.-lbs. (23 N-m) torque and tighten magneto end cover cap screws to 120 in.-lbs. (14 N'm) torque. Remove Vs-inch (3.18 mm) rods. Coat threads of timing hole screws with Permatex or equivalent and install screws with fiber sealing washers.

Fig. B68 —Insert f/8-/nc/i (3.19 mm) rod through timing hole in covers and into hoie in balance weights when instaiiing cover assembiies. Piston must be at TDC,

Fig. B66—View showing baiancer drive gear (magneto end) being timed. With piston at TDC, insert i/4'inch (6.35 mm) rod through timing hoie in crankshaft bearing support plate.

284

Illustrations courtesy of Briggs & Stratton Co rp.