40C Adjustment Questions

John_S

Rear Admiral
Joined
Jun 21, 2004
Messages
4,269
While at camp last week, decided to do some tune-up work on our '85 Nissan 40C. I have the aftermarket manual, not the Nissan, so plese be polite ;)

Pilot Screw: Manual mentions this, and for most motors indicates a specific turn adjustment, ie lightly seated and back out X turns. No further adjustment procedure. I would like to understand what this adjustment is for. Is the pilot screw the same as idle mixture screw? If it is just a gross adjustment, does anyone have the turns for a '85 40C?

Static Timing and Syncing to throttle: Spec is 25 degrees BTDC at WOT and 2 degrees ATDC at idle. I can get one or the other, but not both. If set to 25 at wot, idle is about 1-2 degrees BTDC. (this is the way it was, and is currently set) This is limited by the arm hitting the stop, which doesn't have an adjustment screw. To get to 2 degrees AFTC, I would have to modify the arm to get it to travel that far. If set to 2 ATDC at idle, carb throttle will prevent advance from reaching 25 BTDC. The manual is quite fuzzy on how it is synced to throttle. Does anyone know what the static timing should be when the carb throttle roller is at the "R" or "S" point on the cam?

Coil Resistance: The secondary resistance is lower than the book spec, but is consistant for both coils. Does someone have that spec so I could compare?

PS: Yes, I will be buying the factory manual :) Just would like the data ASAP, for heading back on Thursday AM. Thx.
 

TOHATSU GURU

Admiral
Joined
Jul 22, 2004
Messages
6,164
Re: 40C Adjustment Questions

John,

The pilot screw is the air mixture screw...Translator's are different from manual to manual so we get different words. Initial setting is 1 1/4 and then adjust from there. The coil Primary is .2 - .3 and the Secondary is 4.1 - 6.1 K. I can't post the timing procedure due to a copyright issue.
 
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