Gravely Convertible 10 Shop Manual 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.
IGNITION TIMING PROCEDURE
Engines are equipped with a timing sight hole in either the bearing plate or in the blower housing. A snap
button is used to cover the hole. The button is easily pried loose with a screwdriver so that the timing marks
can be observed. Two timing marks are stamped on the flywheel -- the T mark indicates Top Dead Center
(TDC) while the S or SP mark indicates the spark or Spark Run point which is 200 before top dead center.
Two methods can be used for timing -- the timing light method is the more precise way of achieving exact
timing. The timing light can be used with magneto ignition systems.
METHOD 1 - STATIC TIMING: Remove breaker point cover and remove spark plug lead to prevent
unintentional starting. Rotate engine by hand in direction of normal rotation (clockwise when viewed
flywheel end). Points should just begin to break as the S or SP mark appears in the center
of the timing sight hole. Continue rotating engine until points reach maximum opening. Measure gap with
feeler gauge -- gap should be .020 fully open. If necessary, loosen point gap adjustment screw and readjust
gap to .020" full open. Maximum gap setting can vary a few thousandths (.018 - .022") to achieve smoothest
running. Securely tighten adjusting screw after timing. This provides a method of timing in order to start the
engine after replacing the points. Precise timing with a timing light is required.
METHOD 2 - TIMING LIGHT: Several different types of timing lights are available -- follow
manufacturer's instructions for type used. The following timing procedure can be used with most timing
lights:
A. Remove high tension lead at spark plug -- wrap one end of a short piece of fine wire around spark plug
terminal. Reconnect lead to terminal -- free end of wire must protrude from under boot.
Figure 9 Adjusting Breaker Point Gap
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