New to magnetos

Anonymous-0 · Dec 24, 2008

Got a farmall A. and it has a magneto on it. Block was froze up so i had to take it all apart. Don't know if the mag was good or not. Could anybody tell me how to check it to see if it's good. The tractor has been sitting for 15 years.
Thanks TO

Andy Motteberg · Dec 24, 2008

The mag more than likely needs work if it has not been run in 15 years. To check for spark on a H-4 magneto, put a wire in the coil cover cap terminal and hold the other end of the wire close to the mag housing, (or put the other end of the wire to a spark plug and tape the spark plug securely to the magneto). Take a wrench or pliers and turn the magneto drive coupler clockwise several times while looking at the spark plug. If there is a spark at the plug, the mag has spark. You want a hot (blue) spark. The mag should impulse "snap" while you turn it, if not, it needs work. Many people rebuild mags, or they are easy to do yourself.

Jonathan Mirgon · Dec 25, 2008

If you find the mag to be bad, You can also change over to a distributor type ignition. One can be picked up off of e-bay for around 20.00. You can replace points condensor and rotor on your new 20.00 distributor and have a good working system for less than a mag rebuild. You would also need to change your ignition on off switch. You could use a generic one from an auto supply store for around 5.00. or spring for the high dollar IH switch. Either way if it is a working tractor I believe the distribtor change over would be cheaper. Good luck with your change over/ repair.

Anonymous-0 · Dec 25, 2008

When I compare magnetos to distributors and especially if the engine came with a magneto, I would much rather have the magneto. Several reasons...one is leavein' the switch on will burn the points up in a dist. I don't think it hurts a magneto.
Some of You might recall the schoolin' I got recently dealin' with the wico mag. on the "A". Gene Bender sold Me a H4 for the "A" but I got it runnin' with the wico.
Gene Bender is sharp when it comes to magnetoes, He might have another H4 an/or parts.
Call Steve at Mainly Magnetos..207 834 7309. He can talk You thru any problem with the mag and has every part You need.
Fix the H4...The schoolin' You get now may be helpful later

Wild Bill

JT · Dec 26, 2008

I am a mag person, I have taken the distributor off every tractor I own and put the H4 mag on them. I like them, they start easier, don't need a battery, very simple to work on, any one with any mechanical sense can fix a mag. The impulse normally quits becasue the pawls get stuck or worn, points, condensor, coil,vey simple.
Jim

Clarkbug · Dec 26, 2008

Just to add to the general opinion of keeping a mag, someone on here had posted a link to the Blue Ribbon manual on servicing a magneto. I dont know who it was, but if you do some digging to see where it was, you might be able to find some helpful information.

LenNH · Jan 2, 2009

Just a note: Leaving the switch "on" doesn"t hurt the mag. It doesn"t really do anything except allow the mag to circulate the current it creates. When the mag switch is "off," it just sends current to ground.
Here's one to think about: Recently, a local pilot was on approach to an airport when his engine quite dead. He knew he couldn't make the field and would run into a mountainside if he continued. He opted to land on an interstate that ran near the airport. Like just about all airplane engines, his had dual mags. His mag switch shorted out BOTH MAGS! His fifty years of flying really came in handy. He landed perfectly, somehow missing the cars on the road. The plane was towed back to the airport for repairs. Apparently nothing he could do in the air. Every pilot thinks about moments like that one. Us tractor guys just leave the old beast in the field and write the forum for advice!

New to magnetos

Anonymous-0

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Andy Motteberg

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Jonathan Mirgon

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Anonymous-0

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JT

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Clarkbug

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LenNH

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