H4 magneto Checked and gone through, no fire

[Daniel Dillon]

Tried to reply to similar thread but it kicked me here. I have a 1941 H and I had to buy a new coil about 15 years ago as it would start great when cold but hard starting when hot so I figured the original coil was breaking down under heat a new coil fixed me right up. Mine ran great up until 5 or 6 years ago when I parked it due to rear tire rotted and blew out on me, I usually start and run my equipment from time to time but life side tracked me and it had been about 4 years since I last started and ran my H, just got around to replacing rear tire, cleaned the carb etc put a new battery in it and no fire! from ignition? totally went through my magneto checking for ground problems can't find any replaced points and condenser, tested coil seems ok .5 ohm primary and 12.4K ohm secondary ( same as when it was first replaced ) cleaned everything up still no fire ???
 

[Janicholson]

Is the rotor in time? and did you check to be sure the points were not shorted to ground. TRhe reason for no spark could have changed from what originally caused it to things you may have done (not a flame) Jim
 

[Michael Soldan]

Take some fine emery cloth and fold it in half,insert between the points and rub and rub until you are tired of rubbing and then rub it for five more minutes,then try starting. I had a mag M and I couldn't solve it until I took the mag to an ignition specialist,he just smiled,rubbbed the points for several minutes,said there you go ,no charge..went home,put the mag back on,two cranks and the M was running..give it a try!
 

[Daniel Dillon]

Well in response to both, the points are new but I will rub the contacts, timing has not been changed or touched, I am very careful to be sure everything is aligned just as it was when I first pulled the mag, But even if timing was out should I not get a spark indication directly from the secondary side of coil. I am confused as continuity is good with no grounding to anything, except points show continuity to ground when my coil is hooked up, but I read this is normal since resistance is so low on the primary side. If points and condenser are new and have been replaced, what could possible change by just sitting for 4 years.
 

[Janicholson]

The points do neeed polishing, they are often covered with factory corrosion inhibitor. If the rotor shaft is in time with the cam, it should operate. Jim
 

[Tom Fleming]

Well, to be clear, just because the coil was new 3-4 years ago, does not mean that it has not broken down since then. If you have checked timing (internal and external), mag internal wires, and points, and all checks fine, it could very well be the coil.

I have used old original spare coils off the shelf, and they are still running. I have put at least 2 new coils in over the years, only to have them fail. you might try a new coil cover just to see if there are issues there. on the wire from the coil to the points, be sure that there is good continuity from the wire to the terminal.

Keep us posted as you work through this. I truly cannot think of other things to try that have not already been posted.
 

[El Toro]

Touch the magnets in your mag with a flatblade screwdriver to see if they have strong magnetism. They need to attract with a lot of effort in order to create a hot spark when they pass by the coil. Hal
 

[Daniel Dillon]

Yes they seem plenty strong in that dept.
 

[Daniel Dillon]

Oh I will keep you all updated I did dress the points contacts ( even
though they are new ) it was suggested I do so anyway, and I see
spark at the points just hand turning the mag I hope that is a good
sign
 

[Daniel Dillon]

did just that and getting spark at points just hand turning, will pop it all back on in the morning and see if i get the big spark where I need it now
 

[Daniel Dillon]

Yeah I hope this takes care of it, need my H running, getting old to do some of grunting around the yard by hand :^) I know I shouldn't have let it sit as long as I did but getting back to it now has only rekindled my tractor interest and got me to thinking about the one I have never owned and always wanted, maybe one of these days I will park a Farmall 560 diesel next to my H
 

[El Toro]

If you have battery start you can convert your mag to a distributor using an auto type coil.

You would need an ignition switch and wire to run voltage to the switch and to the coil then to the points. Disconnect the coil wire at the points from the mag's coil. Hal
 

[Janicholson]

Is the impulse coupling clicking as it is rotated (by hand or on the tractor)? if not, that is the issue. It must latch then release to generate enough spark to start. once started it is rotating fast enough to make spark. Jim
 

[Daniel Dillon]

Thanks I have considered that but was not sure, but that verifies that notion and it may go that way. I have tried to maintain a happy medium with this tractor keeping it OEM for the most part and I like the mag ignition set up, but if indeed my mag coil is getting goofy they don"t exactly give those things away :^)
 

[Daniel Dillon]

Well the suggestion of dressing the point contacts, on those new points seemed to be the culprit, did that! got spark at em with just hand turning put the mag back on the tractor, lined my timing mark back up, maybe 3 revolutions on the starter and it fired right up after sitting four years, purrs like a kitten.