JLO L/RM252 ENGINE MECHANICS HANDBOOK Table of Contents – Page 1 of 1 PREFACE TECHNICAL DATA OPERATING - AND MAINTENANCE INSTRUCTIONS A. BEFORE STARTING B. SERVICE AND MAINTENANCE C. ADDITIONAL INSTRUCTIONS D.
L/RM 252 MECHANIC'S HANDBOOK
MOTOR SERVICE 1 U 7 4 4 5 1
CONTENTS Page General vic of engine assembl 1 Table of contents 2 Preface 3 Technical data 4 Operating and maintenance instructions 5- 6 Assembly group 1 recoil 7- 8 starter 2flywheel,ignitionsystems 9-10 3 timing procedure 11-12 4 speed control RM 252 flyball governor L 252 top speed limiter 13-16 17-18 carburettor, carburettordata 19-20 5 piston, 6 cylinder 21-22 crankcase, 7 crankshaft RM 252 L 252 23-24 25-26 Table of specification 27-28 Notes 29 Index of sales offic
This Mechanic's Handbook contains comprehensive information to properly operate, service, and repair JLO engine modelsL 252 and RM 252. The repair procedures are described in detail and are supplemented by useful illustrations. 1. Each assembly group is subdivided into DISASSEMBLY and ASSEMBLY. The illustration numbers shown in the general view on page 1 refer to the individual assembly groups in the procedure section. 2.
Type L/RM 252 Piston displacement 247 cm³ (15.057 in³) Stroke 66 mm (2.598") Bore 69 nun (2.7165") Compression ratio 7:1 CHAMPION BERUBOSCH L86C, L87YC W7AC Spark plug Spark plug gap 175/14C (Heat value 145-225) 0 . 5 mm (0.020") Sparkplugthread M 14x1.25 Timing BTDC 2.8 - Breaker 0.3 - 0.4 point gap - 12.7 mm long 3.2 mm (0.110" to 0.126") mm (0.012" to 0.016") Minimum Maximum internal ignition coil, primary resistance 1.60 O h m s 2 .
Operating- and Maintenance I n s t r u c t i o n s A. Before starting 1. 2. Refueling Mixture ratio -please see Technical Data Engine Check that cooling fins of cylinder and air holes are free from dirt to prevent overheating of the engine. 3. Air filter: Be sure that al filter connections (clamps) are tight. Oil bath filter: Check oil level, refill if necessary. 4. Starting 4.1 Coldengine Shift throttle lever into 'RUN' position.
C Additional Instructions 1. Alr Intake filter Keepdust and dirt out of the engine to avoid premature wear. If engineisoperatedlndusty ordirty environment,the air filtermay haveto be cleaned in short intervals. 1.1 Paper elementfilter: Blow out with air against normal directionof airflow. Replace wetor very dirty cartridges. 1.2 Oil bath filter: Change oil (filling qty. 160- 180 cm³ SAE 30)and observe indicated mark! D. General Trouble Shooting Remedy: Possiblecause: 1. Englne does not start 1.
Assembly group1 RECOI L STARTER DISASSEMBLY 1.1. (1a) out of handle ( 2 ) and untie. 1 Pull knot 2 Allow rope (1) to retract slowly. 3 Remove nut ( 3 ) and parts ( 5 , 6 , 8 , 9 ) 4 To prevent. the recoil spring from uncoiling (see illustration II), rotate rope pulley (10) back and forth to disengage inner spring eye and carefully lift out of housing ( 7 ) . 5 Remove rope (1) from - (illustration I). rope pulley (10).
I 5 6 7 I le 2 11 10 6a Oa
Assembly group 2 FLYWHEEL, IGNITION SYSTEMS Special JLO Tools Flywheel puller (11) 444.31.843.100 DISASSEMBLY 2.1. 1 Remove screws (1) with lock washer (2) carrier (3). 2 Remove screws ( 4 ) with lock washer (5) andfan cover (6). 3 Remove hex. nut (7). spring washer (8), and flat washer (9). 4 To pull off flywheel (10) use puller (II). Unless magnetic flywheel (25) is defective it need not be removed from fanwheel (10). To separate magnetic flywheel (25) from fanwheel remove hex.
cam 15 14 13 25 clockwise erclockwise r o t a t i o n \
Assembly group 3 PROCEDURE Special J L O Tools Timing gauge (1) 441.31.875.000 Timing light (2) 000.15.330.000 TIMING DATA: - Engine Model - - .126 inches (2.8 - 3.2 mm) .016 inches (0.3 - mm) TimingBTDC .110 Breaker Point Gap .012 Spark plug gap .020 inches - L/RM 252 0.4 (0.5 mm) PREPARATIONS 3.1. 1 Screw timing gauge (1) into spark plug hole of cylinder head. 2 Connect one lead of timing light to engine ground, the other lead to the disconnected wire of theignition system.
8 armatureplate (11) generator ignition generating netted t o k i l l switch) 9 yellow/black. I 1 l e a d s when the coil is utilized.
Assembly group 4 SPEEDCONTROL RM 252 FLYBALL GOVERNOR Special JLO Tools Vibration tachometer 000.15.300.100 DISASSEMBLY 4.1. nut (21),washer (18), and cover (17). 1 Remove 2 Disconnect throttle cable noting the hole position for re-assembly. Remove clip (9) from linkage and unhook linkage (1). 3 When removing lever (2) note into which of the 5 holes the governor spring (3) is hooked. To remove lever (2), remove lock nut (16), spring washer (15), steel washers (14), and plastic washer (12).
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Assembly group 4 ADJUSTMENT INSTRUCTIONS-MECHANICAL Special JLO Tools Vibration tachometer 000.15.300.100 STOP-, IDLE-, AND NO-LOAD ADJUSTMENT with the blade fitted NOTE : Check main and idle jet of carburettor for cleanliness. Set air adjusting screw (7) (it should be set 1/2 a turn out). Preparations: 1. Move both speed lever (Max.) position. (1) and throttle lever on mower handle into 2.
e No-loadadjustment a t s p e e dl e v e r b ys p r i n gp o s i t i o n i n g bore A approx. 2750 rpm B 2900 " C D E ( / wire 1.5 B(C) wire c o v eoru, t e r 3050 3200 " 3400 " p r e c i s e a d j u s t m e n t bybendingtongue max 3 . 0 mm correspondwithapprox.100 at lever rpm I + - h i g h e rn o - l o a d lower " " rpm c a r b u r e t t o rs u r v e y r e f .
Assembly group 4 SPEEDCONTROL L 252 TOPSPEED LIMITER Special JLO Tools - Vibration Tachometer Type 000.15.300.100 DISASSEMBLY 4.3. 1 Remove carburettor from intake manifold and disconnect air vane rod (1) from butterfly lever ( 2 ) (see illustr. III and IV). NOTE : T h e butterfly lever ( 2 ) is positioned by 2 flats on the butterfly spindle. When removing the lever, note its original position (see ill. IV) . 2 Carefully unhook spring 3 Loosen hex.
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Assembly group 5 CARBURETTOR, CARBURETTOR DATA DISASSEMBLY 5.1. 1 Remove air filter from carburettor (1). For filter maintenance please rever structions on page5/6. 2 Close fuel shut-off valve on tank and remove fuel line from carburettor. Remove clip (2), governor rod (3), loosen screw (4), remove carburettor (1) from intake manifold. 3 Remove fuel line connection (36), gasket (35), idle jet ment screw (18),and spring (19). to in- (5), gasket ( 6 ) .
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Assembly group 6 PISTON, CYLINDER DISASSEMBLY 6.1. 1 Loosen nuts (1) and remove spring washers (2), cylinder head (3), and gasket (4) Remove bolt (18), spring washer (17), and air guide (16), if these parts aremounted. 2 Loosen cylinder base nuts (5) and remove spring washers (6), and pull off cylinder (7). Discard gasket (8). 3 Remove circlips (9). Push or tap out wrist pin, and remove piston (11). 4 Remove thrust washer (12) and needle bearing (13). .
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Assembly group 7 CRANKCASE,CRANKSHAFT-RM 252 Special JLO Tools Puller 444.31.807.000 Pair of half shells 444.31.072.000 Retaining ring 444.31.071.100 (10) (10) (10) DISASSEMBLY 7.1. 1 Loosen bolts (3) and remove spring washers (4). 2 Pull crankcase pto side (2) off crankshaft (5). Slide fit of ball bearing crankcase (5) allowsdisassembly without heating up. Discard gasket (22). 3 Remove washer (7) and complete thrust bearing assembly (11) from the crankshaft ( 5 ) . Remove balls (13).
I 19 11 5 18 e b 21 x 60 x 0.2 0 0 0 . 4 0 . 4 9 0 . 9 6408 (10) Axial play of 0 . 1 to 0 . 1 to 0 . 2 to 0.4 0.4 0.4 24 2 1 0 DIN 9 8 8 a crankshaft Measurement above above 29.7 to 2 9 . 9 2 9 . 9 to 3 0 . 1 3 0 . 1 to 30.2.
Assembly group 7 CRANKCASE, CRANKSHAFT Special JLO Tools Puller 444.31.807.000 Pair of half shells444.31.072.000 Retaining ring 444.31.071.100 (10) (10) (10) DISASSEMBLY 7.3. 1 Loosen screw ( 3 ) and remove spring washers(4). 2 To separate crankcase halves (1+2), heat them to approx. 212°F (100°C). Lift housing that pto shaft end hangs free and carefully tap crankshaft with plastic hammer out of crankcase. Discard gasket (7). Pry or knockout oil seals ( 6 ) (see ill. I).
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TABLE OF SPEC I F I Dim. Ref. ON Minimum mm (inch) Maximum Bore new mm (inch) Repair required 69,000 (2.7165) 69,019 (2.7173) 69,169 (2.7232) mm) 69,500 (2.7362 69,519 (2.7370) 69,669 (2.7429) 2nd oversize (+1.0 mm) 70,000 (2.7560 70,019 (2.7567) 70,169 (2.7626) B ring groove width, piston top 2,580 (0.1016) 2,600 (0.1024) 2,700 (0.1063) C.D center, bottom 2,565 (0.1010) 2,580 (0.1016) 2,680 (0.1055) ring groove dia. 62,51 (2.461) 62,7 (2.469) 1st oversize 62,91 (2.
NOTE : Piston and cylinder ought to be replaced if the max. play between piston skirt and cylinder wall exceeds 0.35 mm. Depending on engine typ, the piston ring end play should not exceed 0.10 to 0.12 mm. COMMENTS : 1. Piston rings: All three piston rings have to be replaced if piston ring end gap exceeds the max. dimension stated in table item "F". Ring end gap has to be measured in the bore of a new cylinder. 2.
1620 Pinneberg 041 01/21 40 Telex 2 189 113 Telefax 0 41 01 69 12 Pinneberg fin der PRODUCTSCOMPANY
