Magneto Mystery

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   Put my B back together to mow with it last week. I got the back yard mowed, then it quit running. I had a friend drag me around till it started again. Except it would only run on cylinder #4, we took the cap off the mag and cleaned everything put it back together and it would only run on #3. 

We took the plug wires off that weren't firing and put a screwdriver in the cap in those locations and went to ground with no spark from them. 

We have it narrowed down to the mag for sure, but can't figure why 1 cylinder runs nice n strong while the other 3 won't do anything.

Dave

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countryguy828 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 11 Sep 2009 Location: Arcanum, Ohio Points: 129	Post Options Post Reply Quote countryguy828 Report Post Thanks(0) Quote Reply Topic: Magneto Mystery Posted: 13 Aug 2010 at 11:04am
	Put my B back together to mow with it last week. I got the back yard mowed, then it quit running. I had a friend drag me around till it started again. Except it would only run on cylinder #4, we took the cap off the mag and cleaned everything put it back together and it would only run on #3. We took the plug wires off that weren't firing and put a screwdriver in the cap in those locations and went to ground with no spark from them. We have it narrowed down to the mag for sure, but can't figure why 1 cylinder runs nice n strong while the other 3 won't do anything. Dave

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Gerald J. Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Sep 2009 Location: Hamilton Co, IA Points: 5636	Post Options Post Reply Quote Gerald J. Report Post Thanks(0) Quote Reply Posted: 13 Aug 2010 at 12:29pm
	Broken rotor or gear in the distributor section. Gerald J.

countryguy828 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 11 Sep 2009 Location: Arcanum, Ohio Points: 129	Post Options Post Reply Quote countryguy828 Report Post Thanks(0) Quote Reply Posted: 15 Aug 2010 at 7:49pm
	Gerald got it nailed down pretty close... I took the cover off the mag and was able to turn the rotor easily by finger. Pulled that cover off and the gear looks to be in decent shape. Is it possible the cap just shifted upwards a tad bit and the teeth UN-meshed? I had the cap off to paint and retime. The mag had been out by 90 degrees anyways, #1 was were #3 should have been etc. Next problem, went to grab trusty crank to turn motor over...missing, drove 20 miles to the showgrounds where I last used it, not to be found, must have fallen out while going down the highway or someone found it and borrowed it permantly. Dave

Gerald J. Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Sep 2009 Location: Hamilton Co, IA Points: 5636	Post Options Post Reply Quote Gerald J. Report Post Thanks(0) Quote Reply Posted: 15 Aug 2010 at 8:22pm
	Check the rest of the gears and the bearings. A worn bushing will let the gears slip without having worn the teeth all the way off the gears. I just wore out a drill that way. Gerald J.

Steve in NJ Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Location: Andover, NJ Points: 11899	Post Options Post Reply Quote Steve in NJ Report Post Thanks(0) Quote Reply Posted: 17 Aug 2010 at 7:58am
	Sounds like a bad set of points where the spark is going to the breaker plate. Renew the points/condensor and give it a whirl. If there's been high humidity in your neck of the woods, that'll do it. Steve@B&B

countryguy828 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 11 Sep 2009 Location: Arcanum, Ohio Points: 129	Post Options Post Reply Quote countryguy828 Report Post Thanks(0) Quote Reply Posted: 17 Aug 2010 at 9:06am
	I put the everything back in time yesterday. I slid the cap downward as far as I could and tightened the screws. The rotor gear was engaged with the mag side gear. Took a few cranks(borrowed crank from Massey Pony) but started up like a champ. I was able to get it off the trailer. Don't know how long it will last, that gear will probably need replacing soon, but as cheap as I am, I will wait as long as I can. Maybe someday I will buy a new battery and be done with this cranking business. Already had the starter rebuilt once... Dave

Dick L Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Sep 2009 Location: Edon Ohio Points: 5087	Post Options Post Reply Quote Dick L Report Post Thanks(0) Quote Reply Posted: 17 Aug 2010 at 9:13am
	I would tend to lean toward the points as well. Might want to check the gap. Points that have the lifter on the cam broken and just making contact will act like that. I have reset points that have had that happen in the field and run until I could find time to put in new ones. matter fact my Farmall C needs new points that I had reset last year when the plastic lifter broke and have not replaced them yet. Kinda gotta thank yall for bringing back to mind.

countryguy828 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 11 Sep 2009 Location: Arcanum, Ohio Points: 129	Post Options Post Reply Quote countryguy828 Report Post Thanks(0) Quote Reply Posted: 17 Aug 2010 at 9:20am
	The mag side is fine, the rotor wasn't turning.

Dick L Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Sep 2009 Location: Edon Ohio Points: 5087	Post Options Post Reply Quote Dick L Report Post Thanks(0) Quote Reply Posted: 17 Aug 2010 at 10:54am
	Good Deal, Glad you got it figured out.