Gravely Convertible 10 Shop Manual
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Gravely Convertible 10 Shop Manual

Gravely Convertible 10 Shop Manual

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  • Page 2 INTRODUCTION This manual is designed to provide an in-depth service procedure for the Convertible 10, Convertible 10-A and Convertible 12 tractors. We recommend that the procedure outlined in this manual be followed to provide an ease of repair. This manual is set up using the current recommended service procedures and operations.

  • Page 3: Table Of Contents

    CONTENTS TROUBLESHOOTING (engine) AIR INTAKE SYSTEM FUEL SYSTEM GOVERNOR SYSTEM IGNITION SYSTEM ELECTRICAL SYSTEM ENGINE--GENERAL SERVICE INSPECTION – DISASSEMBLY ENGINE RECONDITIONING ASSEMBLY FITS AND TOLERANCES TRANSMISSION...
  • Page 4 SAFETY PRECAUTIONS IT IS TOO LATE TO REMEMBER WHAT SHOULD HAVE BEEN DONE AFTER THE ACCIDENT HAS HAPPENED. Many hours of lost time and much suffering can be caused by the failure to practice simple safety rules. 1. Make sure the work area is clear of objects that might be picked up and thrown. 2.

  • Page 5: Troubleshooting (Engine)

    TROUBLE SHOOTING (engine) CONDITION POSSIBLE CAUSE Hard Starting or Loss of Power 1. Faulty Ignition. a. Loose or grounded high tension or breaker point leads. b. Improper breaker point gap and timing. c. Defective breaker points. (Check First for Dirty Air Cleaner) d.

  • Page 6: Air Intake System

    AIR INTAKE SYSTEM (all models) The importance of maintaining an air cleaner in proper condition can not be overemphasized! Dirt induced through improperly installed, improperly serviced or inadequate elements, wears out more engines than does long hours of operation. Even a small amount of dirt will wear out a set of piston rings in a few hours. Furthermore, operating with a clogged element causes a richer fuel mixture which can lead to formation of harmful sludge deposits.

  • Page 7: Fuel System

    FUEL SYSTEM (all models) CARBURETOR Carburetors are adjusted in the factory and under normal conditions require no further adjustment. If, however, one of the following conditions exist, readjustment of the carburetor may be needed. CONDITION POSSIBLE CAUSE/PROBABLE REMEDY A. Black, sooty exhaust smoke, engine sluggish. A.
  • Page 8 Figure 3 Side Draft Carburetor Disassembly of Carburetor 1. Remove carburetor from engine. 2. Remove bowl nut, gasket and bowl. When carburetor has bowl drain, remove drain spring, spacer (when used), plug and gasket from inside of bowl. 3. Remove float pin, float, needle and needle seat. Check float for dents, leaks and wear on float lip or in float pin holes.

  • Page 9: Governor System

    FUEL PUMP The mechanical pump operates off a cam on the camshaft. The fuel pump lever rides on the cam and transmits this mechanical action to a diaphragm within the pump body. Reconditioning Procedure: 1. Remove fuel lines and mounting screws holding pump to engine.
  • Page 10 Through external linkage, the action of the crossshaft is transmitted to the throttle (or butterfly) valve in the carburetor. When the engine, is at rest, the tension of the governor spring should hold the throttle valve in open position. When a normal load is applied and engine (and governor) speed tends to decrease, the resulting rotation of the cross shaft acts against the governor spring to open the throttle valve wider which, in turn, admits more fuel and restores engine speed.
  • Page 11 SENSITIVITY ADJUSTMENT - K241, K301 On the K241, K301 governor sensitivity can be adjusted by repositioning the governor spring in the holes on the governor arm and speed control brackets. If set too sensitive, speed surging will occur with change of load.

  • Page 12: Ignition System

    IGNITION SYSTEM When checking out an ignition system, start with the components that require most frequent service or adjustment. Hard starting, roughness, low power and erratic operation are often attributed to faulty ignition. All components must be in top condition and the ignition spark must be properly timed to maintain good performance.
  • Page 13 Figure 8 Typical Magneto Ignition Coil Always replace badly burned or pitted breaker points. A certain amount of build up or metal transfer occurs under normal operating conditions; however, if this occurs too frequently and becomes excessive, the condenser may be at fault -- see Condenser Service for details. Slightly pitted points can be dressed down with a point file, although this should be done only as a temporary field fix Replace points at first opportunity after filing.
  • Page 14 PERMANENT MAGNETS If the strength of a permanent magnet is suspected as the cause of magneto trouble, a simple rough test will indicate if its field strength is sufficient. With the flywheel removed, place the blade of a screwdriver (non-magnetized) within one inch of the permanent magnet. If the field strength is sufficient, the blade will be quickly pulled to the magnet.
  • Page 15 Figure 10 Typical Breakerless - Alternator System (Schematic) Figure 11 Wiring Connection Detail on Trigger Module...
  • Page 16 ( Note: Step A for timing lights with alligator clips - some lights have sharp prongs on spark lead - on these simply push prong thru boot until it, contacts metal connector.) B. Connect one timing light lead to the wire that has just been wrapped around spark plug terminal. C.

  • Page 17: Electrical System

    projection on flywheel passes the trigger module, the flashlight tester should turn on, or if an ohmmeter is used, a 5 to 10 ohm resistance should be indicated. Before being triggered, an open circuit should be indicated. Replace the trigger module if wrong results are obtained from any of these tests. AC Leads and Winding: If ignition trouble persists after the system checks out in each of the foregoing tests, the AC leads or ignition windings are probably faulty.
  • Page 18 1. Regularly check level of electrolyte - add water as necessary to maintain level above plates - do not overfill as this can cause poor performance or early failure due to loss of electrolyte. 2. Keep terminals and top of battery clean. Wash with baking soda and rinse with clear water. Do not allow soda solution to enter cells.
  • Page 19 Figure 12 Motor - Generator, Cutaway View Figure 13 Undercutting Mica On Commutator be cleaned and repacked with ball bearing grease upon disassembly of the motor-generator. The armature shaft should be wiped clean and coated with a light grade engine oil. MOTOR TESTS: If unit fails to crank properly, inspect entire cranking circuit for loose or badly corroded connections and damaged wiring.
  • Page 20 4. The armature or field coils must not be cleaned in degreasing tank or with degreasing compounds since insulation damage might occur. Ball bearings should be thoroughly cleaned and repacked with high melting point ball bearing grease. Other parts should be cleaned and carefully inspected for wear or other damage.
  • Page 21 adjustment is at least 0.5 volt less than the current voltage regulator unit setting. This should be 12.8 volts. Current-Voltage Regulator Unit: This requires two inspections and adjustments: The armature air gap and the voltage setting. Disconnect battery before making these adjustments. 1.
  • Page 22 MAGNETO-ALTERNATOR SYSTEMS (C-10A and C-12) The 10 Amp Magneto-Alternator System consists of a magneto ignition circuit and a battery charging or alternator circuit. This system should not be confused with other magneto-alternator systems which provide energy for ignition and lighting but do not have battery charging capabilities. The alternator system consists of three major components: a permanent magnet ring bolted to the inside rim of the flywheel, an alternator stator assembly which is affixed to the engine bearing plate and a rectifier- regulator unit which is externally mounted on the tractor.
  • Page 23 TROUBLE ANALYSIS 10 AMP MAGNETO – ALTERNATOR CONDITION: NO CHARGE TO BATTERY POSSIBLE FAULT/REMEDY TEST A - Disconnect B+ cable at positive (+) terminal of battery. Connect DC Voltmeter between B+ cable and ground. With engine running at full speed (no load), check DC voltage: A-1 - Alternator system OK - ammeter may be giving false A-1 - If above 14 volts.
  • Page 24 ALTERNATOR CHARGING-BATTERY IGNITION SYSTEM (15 AMP SHOWN) system. The 15 amp unit is slightly larger, physically, than the 10 amp unit. Other main differences are found in the ceramic magnet ring and the alternator stator with more posts and windings which accounts for the higher output than the 10 amp system.
  • Page 25 posts are wound to provide energy for ignition. The ignition winding on the breakerless circuits are of very thin wire which is covered by an epoxy - be careful when installing the flywheel not to touch the sharp edges against the wires as they can be easily cut in spite of the protective covering.
  • Page 26 Figure 19 Compact Starting Motor...
  • Page 27 COMPACT STARTING MOTOR (C-10A and C-12) The compact starting motors used with magneto-alternator (ignition and battery charging) systems, use Bendix type drives to engage and disengage from the engine. OPERATION: When the starting circuit is closed and the armature starts to rotate, the Bendix drive pinion moves laterally on a splined sleeve into mesh with the flywheel ring gear.
  • Page 28 MOUNTING-ALIGNMENT: Make sure the special mounting bolts (and lock washers) are used when reinstalling starter. In addition to securing the starter to the machined surface on the crankcase, these special bolts provide proper alignment of the Bendix drive gear to the ring gear on the engine. Use of ordinary bolts will allow the starter to shift which could result in clashing and damage to the gears.
  • Page 29 The PM starters are pre-lubricated during assembly and further lubrication is not required unless the starter is diassembled for servicing. Service is not required at any specific hourly basis - it should be done only when performance indicates a need for such service. Figure 21 STARTER SERVICE If starting problems develop that cannot be attributed to poor connections, low battery, faulty...

  • Page 30: Engine--General Service

    2. Remove thru bolts. 3. Remove end bracket capscrew from end cap, then turn bracket so that it will not interfere with removal of mounting bracket. 4. Slip mounting bracket and frame off over drive end of armature. 5. Separate end cap from armature - NOTE - Brush springs will probably fall out when brushes pull free of the commutator.
  • Page 31 B. Worn oil seals can cause lack of vacuum. Oil leakage is usually evident around worn oil seals. (See Oil Seal Replacement Instructions). C. Blowby, leaky valves can also cause positive pressures. These conditions can be confirmed by making a compression test on the engine. Construction - "U"...

  • Page 32: Inspection-Disassembly

    B. Engine will have to be motored to a speed of about 1000 RPM. Hold throttle wide open and take several compression readings. Consistant readings of 110 to 120 psi indicate good compression. INSPECTION-DISASSEMBLY When diassembling an engine, carefully inspect and note the physical appearance of each of the components.

  • Page 33: Engine Reconditioning

    pressure. If positive pressures build up within the crankcase from a clogged breather or from piston blow- by, oil will be forced out of an engine at oil seals, gaskets or any other available spot. These are just a few of the more common indicators. Numerous others exist and are obvious to the experienced mechanic.
  • Page 34 Figure 25 Pulling Bearing Plate C. Cylinder bore - If badly scored, excessively worn or tapered or out of round more than .005, reboring if necessary. Use an inside micrometer to determine amount of wear (See Fits and Clearance Section). If cylinder bore is not damaged and is within tolerances, only light deglazing may be necessary.
  • Page 35 CRANKSHAFT 1. Keyways - Gears - If keyways for flywheel are badly worn or chipped, replacement of the crankshaft may be necessary. Broken or badly worn gear teeth will also necessitate replacement of shaft. 2. Crankpin - Inspect crankpin for score marks or metallic pickup. Slight score marks can be cleaned with crocus cloth soaked in oil.
  • Page 36 Figure 29 Measuring Piston Ring End Gap Figure 30 Ring Installation Sequence connecting rod small end are worn beyond limits, they can be reworked to receive the available .005 or .010 oversize piston pins. In many cases, it may be more advantageous to use a new piston-rod assembly rather than to rework the old piston boss and connecting rod.

  • Page 37: Assembly

    Figure 31 Camshaft And Valve Mechanism Figure 32 Valve - Tappet Clearance RING GEAR (C-10A and C-12) If inspection of the ring gear reveals broken, excessively worn or otherwise damaged teeth, the ring gear must be replaced. The ring gear is press fitted into a recess on the outer perimeter of the flywheel. The flywheel must be off the engine for ring gear replacement.
  • Page 38 Figure 34 Governor Gear Assembly In Crankcase d. Tighten holding screw from outside of cylinder block. Screw prevents governor gear from sliding off stub shaft during assembly. Rotate governor gear assembly to be sure holding screw does not contact weight section of gear. Figure 33 Exploded View, Major Components Of Typical Engine 4.
  • Page 39 If gasket is not notched, apply gasket sealer around end of rod (outside block) to seal when bearing plate and gaskets are installed. 5. Crankshaft Installation Place block on base of arbor press and carefully insert tapered end of crankshaft through inner race of antifriction bearing.
  • Page 40 Figure 38 Pressing Bearing In Figure 39 Installing Bearing Plate Figure 40 Crankshaft End Clearance Bearing Plate Piston and Rod Assembly Assemble piston to connecting rod and secure piston pin with retainer rings. Always use new retainer rings. Be sure retainer rings are fully engaged in grooves in piston bosses. b.
  • Page 41 8. Installation of Oil Seals on Crankshaft Guide oil seals into position on crankshaft without damaging lips of seals. Any foreign matter on knife like edge or any bending of seal may cause damage and an oil leak can result. b.
  • Page 42 b. After installing magneto components, run all leads out through hole provided (in 11 o'clock position) on bearing plate. Figure 46 - Typical Crankcase Breather 15. Flywheel a. Place wave washer on crankshaft and place flywheel in position. The square key holds flywheel on shaft.
  • Page 43 19. Blower Housing and Fuel Tank a. The engine is now ready for (1) head baffle, (2) cylinder baffle, and (3) blower housing - assembled in sequence stated. These parts are fastened to engine by cap screws which attach to cylinder head and bearing plate.
  • Page 44 Figure 48 Dimensional Diagram -- Seal Sleeve Figure 49 Dimensional Diagram -- Seal Driver SEAL DRIVER DIMENSION (FIG. 49) K241, K301 8-13/16" 1-11/16" 1.248/1.253" 1.498/1.503" TORQUE VALUES ENGINE MODEL MAJOR ITEMS K241 K301 GOVERNOR ARM LOCKING SCREW A CYLINDER CAPSCREW* 420 in.
  • Page 45 TORQUE VALUES -- STANDARD HARDWARE ITEMS SIZE TORQUE SIZE TORQUE 1/4 - 20 70 in. lbs. 1/2 – 13 50 ft. lbs. 1/4 – 28 85 in. lbs. 1/2 – 20 70 ft. lbs. 5/16 – 18 150 in. lbs. 9/16 –...
  • Page 46 FITS & CLEARANCES SPECIFICATION K241 K301 Bore and stroke 3-1/4x2-7/8 3-3/8x3-1/4 Bore diameter, new 3.250 3.375 Crankshaft end play 003/.020 003/.020 Crankshaft - conn. rod journal size 1.5000/1.4995 1.5000/1.4995 Crankpin - conn. rod side clearance .007/.016 .007/.016 Crankpin length 1.187 1.180 Journal diameter, new 1.575...

  • Page 47: Transmission

    TRANSMISSION TROUBLE ANALYSIS TROUBLE CAUSE DETERMINATION SOLUTION Clutches engaged Tractor drive Bound linkage, missing clevis pins. Repair linkage. wheels will not turn. Bent clutch rods, bent or broken actuating shaft levers. Sheared keys in one or both actuating Replace sheared keys. shaft levers.
  • Page 48 SHIFTING LINKAGE Before assuming that internal transmission problems exist, check all external linkage. Inspect the shifting linkage beginning with the control lever and work towards the transmission. Check for binding. Look for broken or missing cotter pins and sheared keys. CLUTCH ADJUSTMENT Clutch adjustment is necessary anytime clutch slippage occurs.
  • Page 49 Figure 52 Figure 53 When replacing the Forward-Reverse Clutch unit, the planetary gears must be timed. Time Planetary gears as follows: a. Place Sun pinion in bore of front pin plate. b. Secure pin-plate quill to the pin plate with three (3) quill-securing bolts. c.
  • Page 50 Figure 56 Figure 57 Figure 58 Figure 59 To avoid damage to the rear pin plate bushing, it is not recommended that Planetary System be further disassembled unless definite problems exist. If an unreasonable amount of play is noticed in the system: a.
  • Page 51 DIFFERENTIAL Before assuming internal swiftamatic difficulties, inspect the external linkage and parts for binding. Carefully check the following: 1. Check linkage for binding, sheared spring pin, loose nuts or debris build up. 2. Check to see that the shifter arm is not binding on the stationary pivot. 3.
  • Page 52 16. Reassemble the differential mechanism. Use new needle thrust bearings if any other part have been replaced. Assemble on two opposite spider arms in this sequence: spider gear, shifting train pinion, needle thrust bearing, needle thrust race, shims, spider thrust washer. On the two remaining spider arms, assemble in this sequence, spider gear and thrust spacer.
  • Page 53 Figure 60 Figure 61 Figure 62 Figure 63 POWER TAKE OFF (PTO) If it becomes difficult to shift the power takeoff in and out of gear, check external linkage for binding. To examine the PTO, remove attachment-boss plate on the front of advance casting. At this point the dog gear and shifting eccentrics are exposed.

This manual is also suitable for:

Convertible 10aConvertible 12

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