Re: 1973 .. 85hp shift probs


OK, Steve. Zero (0) is only used to set the block pointer and distributor to top dead center. The line , not the 0 is the top dead center mark. So, you first find actual top dead center by either using the special tool or a screwdriver or probe of some sort. Probe through the top spark plug hole and turn the flywheel until the piston is at the top of its movement. Take your time and be fussy here.
Now, go to the front of the engine above the top carb and set the long line on the pointer to the 0 line on the flywheel by loosening the screws and sliding the pointer.
At the distributor, loosen the two mounting bolts, swing the distributor in, and set the pulley so that the curved line follows the curve of the flywheel and the straight line points directly at it. This will take a bit of skill as the pulley will move when you pull out on the distributor mount to tighten the belt.
Set belt tension: A .010 feeler gauge when pointed to the center of the belt should deflect the belt about 1/8 to 3/16 inch before bending. If the distributor belt is too tight, the engine WILL have shifting problems.
Now the pointer and the distributor are both set to top dead center with the #1 piston at top dead center. The zero mark has done its job and is no longer important.
Push the control handle to wide open throttle--as far as it will go. Remove the propeller for safety and remove and ground all three sparkplugs. With the ignition key on, slowly rotate the flywheel by hand in a clockwise direction (looking down)until the #1 plug sparks. Adjust the screw between the two black plastic pieces on the distributor until the spark is at 32 degrees before top dead center. You can also use 30 degrees if you want to be safer.
The line between the 3 and 6 is the 36 degree line. To adjust spark timing, adjust the distributor until the 36 line is four small lines to the left of the long line on the pointer. The flywheel in the third photo has a decal and only a single line on the pointer. You can see that the 32 degree mark is set at the line on the pointer.