Farmall H miss I cannot find!

Wayne Rimathe · Apr 10, 2012

A friend came over to the shop with his H Farmall. Missing on 2 cyl's. Good compression, new points and condenser, rotor, cap, wires, plugs. Plugs are D-21. Should I put in BT-8? Good spark. You hold the wire about 1/4 inch out of the cap and running improves?? Cyl 2 and 3 are the ones missing. I have not checked the timing but I would think that would affect all cyl's?? Same with a bad coil or carb problem? New wires are solid wire and not carbon. Could there be an air leak in the manifold?
Running out of ideas and need some help. Thanks--------

D7fever · Apr 10, 2012

try some Autolite or AC sparkplugs

gene bender · Apr 10, 2012

Why not change those two spark plugs with some new ones or just put them into cycls 1 and 4 and take 1 and 4 into 2 and 3 that will tell you everything. If 2 and 3 still miss bad wires you have an easy problem to solve just do some simple changes. Wouldnt be the first time a "new" plug didnt work its happened to me and brands dont matter.

Leroy · Apr 10, 2012

Used to run that Champion years ago and they went from good to forget about buying, Try new Autolight plugs. Quit AC before going to champions because when they went to the fire ring would put in new set in morning before going to work, clean at noon, next morning start repeating for a week, that was last of AC plugs in tractor.

George Rausch · Apr 10, 2012

I was advised to go to Autolite 388's, set at 0.030 or wider, with Seafoam, with premium gas. It stopped fouling of my plugs.

Eldo case · Apr 10, 2012

Check firing order for crossed wires.

El Toro · Apr 10, 2012

Do you have the plug wires in this firing order on the cap? Hal

2-1
4-3 The rotor rotates CW. Hal
PS: Check the cap to make sure it isn't cracked.

Ken Combs · Apr 10, 2012

"You hold the wire about 1/4 inch out of the cap and running improves?? "

That sounds like bad or fouled plugs. Voltage leaks by through the fouling and never rises enough to jump the gap. Old trick used when worn out cars oil fouled the plugs was to put a gap in the connection to the plug.

The voltage has to rise to a very high level to jump that gap and will fire a marginal plug.

old · Apr 10, 2012

Take the plugs from #1 and 4 and put them in #2 and 3 and take the plugs from #2 and 3 and put them in #1 and 4 and see if the problem follows the plugs. If not then it is a manifold or valve type problem but if it follows the plugs you have bad plugs

Anonymous-0 · Apr 10, 2012

Check the easy stuff first...start with where the plug wires are in the distributor cap. Had a VW give me problems once...same kind of problem, a 4-banger missing on 2 cylinders. Took it to a shop that does imports. When the tech opened the hood, he asked me,"Did you wire that cap from the 1974 ediion of the Chilton's manual?" I said that I did. He said, "Yeah, we see that a lot...they got the picture on distributor rotation reversed."

If the firing order is correct, then check compression. If compression is OK, then start the engine and use a pump oil can to pump some oil around the manifold-to-head gap. If the miss disappears for a little while, replace the mnifold gasket. [You can clean te engine off with degreaser or brake cleaner after it cools.]

Had a friend in years back who bought a Chevy 400 smallblock from a junkyard for a pickup he owned. Once in, the engine ran terrible. Long story short, he found part of the intake plugged up with the biggest mud dobber's nest he'd ever seen.

So start with the simple stuff first.

James Williams · Apr 10, 2012

#2&3 plug wires crossed,its the most common problem

jimmy

Farmall H miss I cannot find!

Wayne Rimathe

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D7fever

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gene bender

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Leroy

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George Rausch

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Eldo case

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El Toro

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Ken Combs

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old

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Anonymous-0

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James Williams

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