Will a bad magneto keep a unit from starting? When I bought the machine the guy said the magneto needed rebuilding. It started the first couple of weeks that I owned it. But now it just turns over.
Of course it will. If the mag is bad you will not get a spark, or only a weak one. It will not run without a spark and not run properly if the spark is weak!
RAB
Thanks. I don't really know much about mags as I was born in 1973. I guess its time to call Mr. Zimmerman and order a new one.
~C.C.~
You might want to look in the local yellow pages for shops that rebuild them. Try Napa, They might be able to direct you. Might be cheaper.
What tractor is it on? Look for the model and make of the magneto. You may be able to just new points and condenser and it will be good as new. Sometimes you have to have the magnets recharged, but that is not as common.
Blake
You rarely need to resort to a complete rebuild. As Blake says, points and condensor (rarely ever). Usual problem is transfer to HT supply to plugs - like damp in the distributor - or corrosion (or oil) on the points surfaces. They do not like overly wide spark gaps (will stress and break down the coil insulation). They can be used as a Ketteringham system with an external coil, if the tractor has an electrical system (battery and generator).
If you have a Wico mag, check the mag output to the distributor side first, to see which side the fault is to be found.
A lot had holes drilled through the sides of the distributor cap to allow condensation moisture to escape.
Check the impulse coupling is working corrrectly if it is cranking slowly.
Rarely does anything else go wrong with them, unless lube is neglected, or they are flooded out with water.
At your old age you should be able to understand a simple electric motor, therefore a simple generator, therefore a mag, 'cos that's all they are - It only uses the principle of a moving conductor in a magnetic field (or vice versa) producing a current and the transformer principle to jack up the generator voltage for the HT,
RAB
If you have a Wico model XH replace the points, condensor , and coil. Alot of times the coils get weak and will shut down after the engine has run for a few minutes . Actually the Wico XH is still being produced.
Quote from: "Blake"What tractor is it on?
Its my '57 OC4.
~C.C.~
Take it off and clamp it in a vise and give everything a good look. Do you have your HG home yet? If so does that mag have a good spark. They will interchange.
No I haven't gotten it home yet. Its still sitting at the dealership. I guess i'll go ahead and bring it home. I went to the local "god almighty of alternators and starters". I took the mag to them to check out for me. They took it in the back, cleaned it up, and gave it back to me. They said they had no means to mess with it. They said there wasn't enough demand for it so they got rid of all they're equipment.
~C.C.~