D-14 Dead Miss

Palpatine · May 25, 2014

I have a D-14 Allis Chalmers. It has run great for a lot of years. Lately it has developed what seems like a dead miss. I"ve noticed what appears to be oil accumulating on the back spark plug. I can clean it, but it gets covered again quickly. The tractor still starts and runs, and it is not smoking at all. It"s just running a little rough.

Any ideas where I should start?

funky_g00 · May 25, 2014

I would first trying moving the fouled plug and/or wire to a different cylinder and see if the problem follows them. If it does the plug, wire or both are the problem and a tune up is in order. If nothing changes then you have either a ring or valve issue.

Palpatine · May 25, 2014

I put a new set of plug wires on it a few months ago. I'll try a new plug and also moving the plug wire and see what happens.

The first couple of times it happened, I would clean the plug and it would run good for a few minutes before it went back to missing. But the last time or two I cleaned the plug, it seemed to have no effect. Maybe the plug is completely fouled now.

maxwell99 · May 26, 2014

If it's oil related Napa can order for you a set of plug extenders.

You screw these units into the head, then screw the spark plug into the extender, it gets the spark farther away from the oil,

They might help you for a while, but in time, you will need to fix the problem.

maxwell99 · May 26, 2014

Forgot,
Also buy a few of the hottest plugs you can buy for that cylinder

If I remember correct, the shorter the electro the hotter the plug or I might have that backward, but a hot plug will fire better in that bad environment for a while,

When they go dead, just install another one an keep on tractoring.

I know this procedure from experience.

ASEguy · May 26, 2014

I would do a compression test to verify if the cylinder has compression. Rule out mechanical issues then head for spark. When I run a compression test, I do all cylinders to get a picture of the mechanical condition of the engine.

Dick L · May 26, 2014

I have not had good luck cleaning a fouled plug more than a coupla time before they short out for good. I try to keep new plugs around and change out a fouled plug when it happens.
Some times you can work the tractor under a heavy load several hours will stop the problem with clean oil.

2 stroke · May 27, 2014

Hey man I have a D-15 salvaged from the scrap-yard, and the engine was locked up. Once I got it unstuck and running she would blow oil from around number 3 spark plug. Well I pulled the engine down and did a in frame on it this past winter and found that the oil ring shot it was the same size of the piston. It may be possible that yours cracked the oil ring, because they are pretty thin compared to the compression rings.

Palpatine · Jun 3, 2014

Well, I put a new spark plug in it, and it ran as smooth as ever. I took it out and drove it around some, and it never missed a lick. I don't use it a lot, but I need it when I need it. I bought an extra plug in case it fouls one in the middle of a project.
I plan to restore it in the near future, as I have done my other two tractors. I'll go through the engine then and fix the real problem. I just want to keep it running good and available until then.

Palpatine · Jun 3, 2014

Well, I bought a new spark plug for it, and now it's running smooth as ever. Hopefully I can keep it going until I'm ready to restore it.

Thanks for everyone's input.

D-14 Dead Miss

Palpatine

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maxwell99

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maxwell99

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ASEguy

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Dick L

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2 stroke

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Palpatine

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