h no spark

KENIND · Sep 26, 2017

About 3 weeks ago drove my 1940 H the local veterans home for a day of show and tell. Tractor started and ran perfect like always since I have owned her. Went out last Thursday to do some work with it and no start. Got lots of gas and cranks over but no start. It has a mag on it and I have never jumped into one of those before. So,I don't have any spark at the plugs and seems to not have any spark at the coil. So where should I start to find out why no spark..........HELP.... Kenny

Charlie M · Sep 26, 2017

Sounds like you have an external coil. Do you have 6 or 12 volts. If its been converted to 12 V the resistor could have died. If its still 6 volts then the problem is somewhere else.

Bob · Sep 26, 2017

Most likely cause is dirty/corroded breaker points. Clean 'em up by drawing a clean piece of white cardstock through them, followed by s spray of electrical contact cleaner with them open, and allow to air-dry.

To access the points, check out the mag service manual linked below... you want to take out 3 identical screws that hold the cover/rotor drive gear assembly to the mag and remove it as a unit, NOT two matching screws that hold the gear cover on, which will get you out of time.

Also, it might not hurt to remove the "kill" wire from the mag and crank it and see if spark returns before tearing into the mag, just in case the "kill" switch or wire to it might have shorted.

http://farmallcub.com/rudi_cub/www.cleancomputes.com/Cub/Blue%20Ribbon%20Service%20Manuals/GSS-5035%20Service%20Manual%20Magnetos/index.html
Manual

teddy52food · Sep 26, 2017

Send your mag to me as I do them cheap as a hobby.

tractorguy2 · Sep 26, 2017

Most likely you need to clean or replace the points. Worst case
scenario would be a bad coil. You can fix it quite easily at
home. You only need a screwdriver, pliers and two 9/16 wrenches.

James Williams · Sep 26, 2017

Teddy,do you do E4A mags

KENIND · Sep 26, 2017

How cheap is cheap?

old · Sep 26, 2017

The most common cause of lack of spark is the points need to be cleaned or replaced simple as that I have seen that so many times I could not tell you how many times I have winched a tractor on the trailer and drove it off just by cleaning the points

teddy52food · Sep 26, 2017

I can work on them but I have nothing for parts on hand.

John T · Sep 26, 2017

The very FIRST thing I try if a mag doesn't fire is to clean/buff/polish the points and check their gap. Its possible to remove gray oxide coating by running a dollar bill through them.

John T

teddy52food · Sep 26, 2017

I do most mags for $25 to $50.00. Plus parts as needed. I just did 3 for $35, but they didn't need much. One a set of points, another just cleaning the points & one needed a coil & condenser. I have a magnet charger and coil & condenser tester. If a coil or condenser tests good I use it.

KENIND · Sep 27, 2017

Thanks everyone!! I am gonna get a set of points and a condenser and dive in head first on the weekend. I sure miss my Dad on instances like this. He work in the local IH shop for 25 years. He knew this stuff like the back of his hand. But passed on before he could teach me about mags. Oh well HERE WE GO!!!!!!!! Thanks again for all the help...........Kenny

h no spark

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Charlie M

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Bob

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old

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