electrical problem

[jazz125us]

i have an 89 nissan ns90a motor. all 3 cylinders have excellent compression and great spark. my problem is that cylinder 2 and 3 do not fire. i have new coils, and cleaned carbs.the top cylinder sucks air into the carb but the bottom 2 don't. my trigger coils are spaced at 3 different distances. it sputters and backfires which seems to think its a timing issue, but i can not see where it would be out of time.

any suggestions, i am all ears

 

[TOHATSU GURU]

Re: electrical problem

Pull the bottom spark plug boot off while the engine is running. If the RPM goes up you have a spun crankshaft.

 

[jazz125us]

Re: electrical problem

no changes in rpms at all. do you happen to know what the spacing is for the trigger coils. cylinder one is at 18 thousanth, and the other two are further away.