Starting Problem, Need Help

[mrrestless]

Engine turns over perfectly with spark plugs removed. Will barely crank over with plugs in (under compression). Wiring harness coming out of the magneto gets very hot (to the point of smoking) if I continue to try cranking it over. The battery is good (not the issue).
Appears that the starter is not getting full battery power and possibly is (partially) shorted out.
This is an older single engine twin. Any ideas?

 

[Joe2tek]

Sounds like you may have a starter issue. If you are overheating the harness, there is a good chance the armature in the starter is failing. It is easy enough to remove it and have it checked first before replacing.

 

[Ckrawiec]

Engine turns over perfectly with spark plugs removed. Will barely crank over with plugs in (under compression). Wiring harness coming out of the magneto gets very hot (to the point of smoking) if I continue to try cranking it over. The battery is good (not the issue).
Appears that the starter is not getting full battery power and possibly is (partially) shorted out.
This is an older single engine twin. Any ideas?

I'm referencing back to my '96 GTX ski with a 787 motor.....cranked fine with plugs out (nice and strong), cranked with more difficulty with plugs in (compression) but still cranked fairly strong.....but would not catch and run. Finally put a little pre-mix directly into the carb throats and she fired briefly

Traced back to carburators (pulse pump actually)....was NOT feeding fuel to the cylinders.....I was blinded to think -> NO WAY could it be carbs.....rebuilt them (with genuine Mikuni parts)...fired right up with no hesitation.

The smoking magneto harness is concerning.....it definately shouldn't do that......the stator/magneto puts out AC voltage to the rectifier, the rectifier converts the AC to DC [13.5 - 14.5 thereabouts] for the ski and battery charging.

 

[mrrestless]

Thanks, I’m quite sure this is not a fuel issue. I also wonder why the stator leads heat up when the draw is on the battery. Thinking if the armature is partially shorted it may be grounding through the reg/rec into stator. Will start troubleshoot with the starter.

 

[mrrestless]

Problem solved. The ground lead from battery was corroded. Current was backfeeding into the stator where it had limited ground, heating up the harness in due course.