Battery draw, flywheel hot

340

Cadet
Joined
Jul 12, 2011
Messages
12
I have a 1995 70hp. Johnson that intermittent will kill the battery overnight, problem never there when I can test for a current draw but the other day while out on the water the engine failed to crank (starter not spinning motor). When I removed the cowl I found that the flywheel and rectifier were hot to the touch while power head cold, what could send voltage through this circuit with engine off/key off?
 

reiddo1

Petty Officer 2nd Class
Joined
Jan 17, 2012
Messages
166
Re: Battery draw, flywheel hot

It could be that the starter solenoid has jammed and you are getting enough current to the starter to heat things up but not enough to turn the engine over. Disconnect the battery cable and starter motor cable from the solenoid and check to see if you have continuity across these solenoid terminals. If you do, then your solenoid is the problem.
 

boobie

Supreme Mariner
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Nov 5, 2009
Messages
20,826
Re: Battery draw, flywheel hot

Sounds like a bad solenoid or some stray current energizing it when the mtr is sitting.
 

Vic.S

Rear Admiral
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May 4, 2004
Messages
4,719
Re: Battery draw, flywheel hot

I'd suspect an intermittently defective rectifier causing current to flow "the wrong way" from battery through the rectifier and stator.
#That is why the flywheel and rectifier were hot
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Battery draw, flywheel hot

+1 on the rectifier. Had a similar issue with one of my motors...
 

340

Cadet
Joined
Jul 12, 2011
Messages
12
Re: Battery draw, flywheel hot

Thanks for the info, I will try those tips, I reconnected the battery this morning and the draw is gone. I know it's going to come back at some point so im going to put the flush cup on it and try to duplicate it so I can test it. I will replace the solenoid anyway and the kill switch in case it is coming apart and applying power to the kill circuit, also saw somewhere in a diagram a blocking diode, not sure what will happen if it fails, and where is it? A couple years ago I had a "no start/no spark condition and replaced the power pack, stator and rectifier because it was so intermittent I replaced all at same time, A month ago I had a "no start/no spark" condition and replaced the power pack (new)and had no spark until I disconnected the yellow wires from the rectifier, one of them would arch when connecting and cause the stator to smoke. I swaped the stator and rectifier back to the originals and engine ran normal, installed the oringinal power pack and no spark. Reinstalled the new power pack and the original stator and rectifier, I burned through 20 gals fuel with no problem until 2 days ago.
 
Last edited:

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Battery draw, flywheel hot

The kill switch doesn't apply power to anything. It shorts the magneto to ground to kill the engine. It's contacts are OPEN when the engine is running. If the solenoid was stuck in the "energized" position (as though the key was in START) the starter would be spinning. Always troubleshoot before you start throwing parts at the issue. Why not simply disconnect things one at a time until the draw goes away.
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,135
Re: Battery draw, flywheel hot

wiggle your stator wires while checking with a multimeter to see if you have a short to ground from the stator wires to the rectifier
 

340

Cadet
Joined
Jul 12, 2011
Messages
12
Re: Battery draw, flywheel hot

Im sorry.. I meant key switch, there are 12volt circuits in there, yes I do have a remote kill switch and don't intend to replace that as I have isolated that as not a problem
 

340

Cadet
Joined
Jul 12, 2011
Messages
12
Re: Battery draw, flywheel hot

have had 2 different stators and rectifiers off of the engine, inspected all of the wiring for chaffing or pinching, the only wiring I havent seen yet is factory taped and no bare spots.
 
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