48 cub with j-4 magneto

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bug
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Joined: Fri Feb 19, 2016 4:49 pm
Zip Code: 72653

48 cub with j-4 magneto

Postby bug » Sat Feb 20, 2016 6:19 pm

Hello this is my first venture on this forum, I have a firing problem that I am wondering if it is the coil. When installing the new coil I am unsure if the metal "flap" on one side
of the coil with a hole in it goes to a mounting bolt.

staninlowerAL
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Re: 48 cub with j-4 magneto

Postby staninlowerAL » Sat Feb 20, 2016 7:47 pm

Welcome to the FORUM. Not enough info to make an assessment. Suggest you download the GSS1012 pdf manual or Rudi's manuals from the link at the top of this page and familiarize yourself with the contents. This link should take you there. http://www.farmallcub.com/[ Sorry, direct links to manual section is not allowed. ]/downloa ... -27-55.pdf Also search the FARMALL CUB forum for this subject. There's lots of information available as the subject is posted on quite frequently. Best to post questions on the FARMALL CUB FORUM as you will get more views and comments there. There are also FORUM members who are specialists in magneto repair. Good Luck, Stan

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Rick Spivey
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Re: 48 cub with j-4 magneto

Postby Rick Spivey » Sat Feb 20, 2016 11:47 pm

Yes, the tab should be bent, if needed, to lay on top of the coil bar, and under the coil hold down stud.
Rick Spivey
'52 Cub ("Great Personality") 148xxx
'48 Cub with FH ("Gunny Cub") 38xxx
'57 Lambretta (a slow work in progress)
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bug
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Re: 48 cub with j-4 magneto

Postby bug » Wed Feb 24, 2016 12:35 pm

Thanks for the help, to go deeper into my problem, my 48 farmall wasn't running well so I changed points and condenser and then no fire, went through all the timing checks to
assure I didn't halve the timing off by 180 or so have even put old points and condenser back on still no fire. Got the idea that the coil might be faulty, checked coil lead to
ground and sure enough it is grounded just like the kill switch was enabled. Installed new coil same grounding situation, so the original question was formed just looking for
an answer. Next question should the "pigtail" lead from the coil to the points condenser post be grounded?

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mva1958
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Re: 48 cub with j-4 magneto

Postby mva1958 » Wed Feb 24, 2016 5:36 pm

Check the plastic insulator that fits on the kill switch post. Case IH can get one for you if yours is cracked or broken. Mine looked intact but it fell apart when I loosened the nut on the switch post, replacing it solved my problem.
If only Mrs. Hoyt and Mrs. Clagwell had gotten along...

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Rick Spivey
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Re: 48 cub with j-4 magneto

Postby Rick Spivey » Wed Feb 24, 2016 6:53 pm

The coil WILL be grounded to the magneto housing by that tab you referred to. It is one end of the primary winding, and the lead to the stud is the other end. You cannot use a continuity check to discern anything when the coil is installed in the mag housing.
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)

bug
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Joined: Fri Feb 19, 2016 4:49 pm
Zip Code: 72653

Re: 48 cub with j-4 magneto

Postby bug » Thu Mar 17, 2016 9:24 pm

Have exhausted all the helpful information so far. Shouldn't the coil still fire regardless of timing? If I remove the coil wire from the center of the distributor cap and hold it
close to ground and crank the engine over wouldn't it fire in this situation?

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John *.?-!.* cub owner
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Re: 48 cub with j-4 magneto

Postby John *.?-!.* cub owner » Thu Mar 17, 2016 10:12 pm

yes, it should fire that way. Assuming you see the rotor turn with the engine so you know the magneto shaft is turning, you need to disconnect wire going to kill switch to make sure it or the switch are not shorted. Next would be to check the terminal inside the mag where the points, condenser, and coil all come together. It is really easy to get the terminals from the condenser or coil against the side of the magneto and ground it out just like the switch was off. If nothing at any of these, verify the insulator and inner and outer spacers for the srud that goes through the side of the magneto are all in place and good.
If you are not part of the solution,
you are part of the problem!!!

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Rick Spivey
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Re: 48 cub with j-4 magneto

Postby Rick Spivey » Fri Mar 18, 2016 4:48 am

Since it happened after you changed the points and condenser, the most obvious culprit would be the stud that goes through the magneto housing. 2 previous posts already suggest this, I'm just stating the obvious here to reiterate. Be sure that connection isn't grounded to the magneto housing. Beyond that, use a points file or rough paper bag to "de-glaze" the new points, sometimes they don't fire as received.
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)


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