824 TRACTOR Starting Engine Magneto Caterpillar

Starting Engine Magneto

Do Not Lubricate The Magneto At Any Point: The bearings are packed with a ball and roller bearing grease when assembled, and this should be replaced only when the magneto is taken to your AVSpare dealer for checking or reconditioning.

Checking Contact Point Opening: Every 1000 service hours check the contact point opening.

To check, first remove the distributor cap. Care should be taken in removing the cap not to damage the gasket. Clean any carbon dust from the inside of the cap and any carbon track from the rotor using a soft cloth, dampened with a non-inflammable cleaning fluid. Remove the distributor rotor, then turn the engine until the contact point bumper block (1) is on one of the highest elevations of the cam. Check the clearance with a thickness gauge between the contact points as illustrated. This clearance should be .015 inch (.38 mm.).

1-Contact point bumper block on one of the highest elevations of the cam.

Adjusting Contact Point Opening: Loosen bracket fastening screws (2) which hold the adjustable contact point bracket and move the bracket by inserting a screwdriver in the slot (3) and turn either clockwise or counterclockwise until the correct point opening is obtained. Then tighten the fastening screws and recheck the adjustment.

2-Bracket fastening screws. 3-Slot.

To Remove the Contact Points: To remove the contact points, remove the spring clamp screw (4) and bracket fastening screws (2) used in adjusting the contact point opening.

4-Spring clamp screw.

Testing: A magneto can be tested when coupled to the engine. Remove the cable from a spark plug (rotate the terminal to facilitate removal), insert a 1/4 inch (6 mm.) bolt or similar metal object into the terminal to contact the wire, and hold the terminal so the end of the bolt is 1/8 inch (3.17 mm.) away from the metal base of the spark plug. Turn the RUN-START switch to the START position to crank the engine, or to the RUN position while hand-cranking the engine. If no spark occurs between the bolt and the spark plug base, disconnect the switch wire from the terminal on the magneto and test again. If a spark now occurs with the switch wire removed, the wire from the magneto to the switch has become grounded or the switch requires replacement. If, with the switch wire off, the magneto still does not fire, remove the magneto as instructed in the next paragraph and take it to your AVSpare dealer for testing.

To Remove the Magneto for Testing: Disconnect the cables from the magneto. One of the cables should be tagged or marked in some convenient manner which will designate the proper position of these cables. Remove the two bolts that hold the magneto to the timing gear cover and lift off the magneto.

To Time the Magneto to the Engine: To time the magneto to the engine, proceed as follows:

1. Locate the "X" mark (1) on the starting engine magneto drive.

1-Mark "X" on magneto drive. 2-Mark "X" on the impulse coupling tang.

2. Turn the magneto impulse coupling until the "X" mark (2) on the tang is in such a position as to line up with the mark on the magneto drive.
3. Install the magneto with the "X" marks together and tighten the bolts.

To Reinstall Magneto Wires: To reconnect the magneto wires proceed as follows:

1. Place the spark plug wire from number 1 cylinder (the cylinder farthest away from the flywheel) into the top wire receptacle of the magneto cap.
2. Install the other spark plug wire.
3. Reconnect ground wire.