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Onan charging


mikeb

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Well, finally found some time to get into my 720 loader tractor to diagnose "electrical issues" as described by a previous, previous owner. Among other things, I found all three wires from the stator severed. I've pulled the flywheel and stator, everything looks to be in good shape except for the wires. Unfortunately, two of the wires are black and one is red. The corresponding wires in the loom are still there, but the wires were severed in such a way that I can't tell which black wire on the stator went to which black wire in the loom. My question is does it matter? At first I didn't think so, believing the wires just made a big loop around the stator windings. But I read Al Eden's Onan Charging article again and in the troubleshooting mode he describes different resistance measurements depending on which black wire your measuring: makes me think maybe there is some difference after all? Anyone out there care to shed some light on this? I'd hate to waste a perfectly good charging system (if it actually works) just because I had the wires backwards. Thanks, Mike Bennett Fresno, CA
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Hey Mike, Yes, it does make a difference! I find them in the wrong positions from time to time. Blk to blk doesn't matter it's a different story blk going to the red. Did you ever get the Onan manual? I'll send one in your email. Do you have a digital ohm meter? If not get one! Last thing, make sure you zero the leads out or know what to offset the meter to get the correct readings! Let me know how it turns out! JP
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Thanks JP! I had the red to red thing figured out :), I was just concerned about the multiple black to blacks. I can't believe someone would actually connect the red to one of the blacks, wow: I guess if common sense were common everybody would have some. I'm not sure I have a formal Onan engine manual. One of the Allis Chalmers service manuals I have has an Onan section in the front of it: 60 or so pages of CCKA and CCKB engine stuff, plus a flat rate schedule for doing work. If you have something different, I'd love to have a copy! :) I have several digital VOM's, thanks for the reminder about zeroing out the meter first when on the ohms scale. BTW, it was a pleasure to finally meet you in person recently on my coast to coast road trip. One of the highlights of the trip was spending an hour or so at your place talking tractors. You have quite a collection! Thanks again, mike bennett fresno, ca
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Mike - How do you think the wires were severed? Curious because mine had some insulation that was cut. I wonder if the flywheel came in contact with them somehow?
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Beeser, I commonly see the wires not returned to under the holder correectly. Vibration and the lack of just replaceing the wire holder lead to the flywheel eating these poor wires.
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quote:
Originally posted by D-17_Dave
Beeser, I commonly see the wires not returned to under the holder correectly. Vibration and the lack of just replaceing the wire holder lead to the flywheel eating these poor wires.
Uh oh, what holder?
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I've seen diff. styles on different engines. I've seen brackets on some and just a thick stiff wire looking holder held in place by the lower right timeing cover bolt. If you've snaked the wires around towards the oil filter they may be fine. But there isn't much room under there for any error and that flywheel looks awfully hungry.
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Come to think of it there was a clip on the back side opposite to the starter. It was one of those C-shaped ones with rubber coating on it. I wonder if it was for the wiring talked about here.
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Hey Beeser, All three wires were severed at the same point: something sharp cut them all at quite an angle. I don't think it was abrasion due to the flywheel: more like a dull cut. Almost as if the engine was dropped/slid on the wires while removing the engine. Once I had soldered all the wires back together and got it all re-installed, I also got nervous with those wires running so close to the flywheel. I took a zip tie and used an open hole on the starter mount to hold the wires in place. Seems to work well, though I needed to space the sheetmetal shroud out at that point with a washer for a little extra clearance. I dunno 'bout the previous owner of this tractor: I found a large wad of electrical tape on the positive battery cable. Curiosity got the better of me and I started to unwrap it. Eventually I found the cable had been severed and someone had stripped some of the insulation away and just loosely twisted the strands back together! ON A BATTERY CABLE! I'm gonna hafta go over this tractor with a fine tooth comb. The goal is to get the engine back in the frame tomorrow or Sunday, and see if I can make her run. Don't know about the fuel system yet, had spark late tonight with the help of a coil from my other Powrmax. Maybe by Thanksgiving I can try out the loader and see what kind of shape it is in.
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