J4 Magneto Question

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mva1958
5+ Years
5+ Years
Posts: 115
Joined: Sun Mar 23, 2014 8:55 am
Zip Code: 23314
Circle of Safety: Y

Re: J4 Magneto Question

Postby mva1958 » Mon Feb 25, 2019 7:33 pm

Jeez you guys are fast - I hoped I'd eliminated my misinformation before anyone saw it, but noooooo....
If only Mrs. Hoyt and Mrs. Clagwell had gotten along...

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Rick Spivey
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Joined: Sun Jul 01, 2007 10:07 pm
Zip Code: 29518
Circle of Safety: Y
Location: SC, Cades 29518

Re: J4 Magneto Question

Postby Rick Spivey » Mon Feb 25, 2019 7:39 pm

No harm, no foul. Not trying to call anyone out, but want to be sure this poster has the correct info to solve his problem. Mags are strange beasts, I happen to love them, but a mag converted to external coil is possibly (imo) the worst of both worlds.
Rick Spivey
'52 Cub ("Great Personality") 148xxx
'48 Cub with FH ("Gunny Cub") 38xxx
'57 Lambretta (a slow work in progress)
'74 Triumph TR6 (Mama's toy)

cjack
Posts: 37
Joined: Sun Sep 02, 2018 12:12 pm
Zip Code: 00000
Tractors Owned: 49 Farmall Cub
Location: Burlington, ON, Canada

Re: J4 Magneto Question

Postby cjack » Mon Feb 25, 2019 11:22 pm

OK. We will pick up new parts tomorrow. We will install new condenser, test, install plug wires (probably not the problem but ours are in bad shape), test, install new points, test, install new coil, test. The coil can be returned if not opened. The other parts are inexpensive.

Priming oil pump - so far we have been hand cranking on assembly lube, not more than 30 or 40 rotations total. But I have a mind to fill with oil and prime before doing more tests. It cannot hurt, thanks for the nudge.

Confirming we have original J4 mag, no battery ignition, and we set the points to 0.013. Although I am now doubting if we cleaned up the points well enough, Anyway, getting a new set tomorrow.

Thanks everyone for all the input.

The plastic insulator and bakelite washer look like new, I suspect Spencer's grandfather replaced them at some point. (The tractor was well cared for and barned until the barn collapsed... farming in northern Ontario did not work out for many folks... the farms were cleared by the lumber companies in the 1800's but there are only inches of soil on top of rock and only cattle farming was barely viable. Long hard winters. That farm is mostly grown in again - back to forest.)

We checked all over that terminal with the Ohmmeter and it is definitely OK - when nothing is connected to it there is infinite resistance to ground.

Glen, the rotor and drive gear are aligned and we removed the slightly cruddy grease and re-greased per instructions.

An electrical engineer friend of mine has a "megger" which is a device that can definitively test the coil. He offered it to us but I would not immediately know what to do with it so if all else fails we will simply swap for the new coil to see what happens. If we do follow up with the megger, we can report back on its wonders.

Thanks again.

Dave F.
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Location: WV, Morgantown

Re: J4 Magneto Question

Postby Dave F. » Mon Feb 25, 2019 11:51 pm

I am curious how would you check a coil with a megger ? I would like to know how ? Thanks Dave F.

cjack
Posts: 37
Joined: Sun Sep 02, 2018 12:12 pm
Zip Code: 00000
Tractors Owned: 49 Farmall Cub
Location: Burlington, ON, Canada

Re: J4 Magneto Question

Postby cjack » Sat Mar 02, 2019 10:50 am

We systematically replaced condenser, spark plug wires, then the points. The problem was with the points. We have a nice blue spark now.

Thanks to everyone for your input.


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