Allis B problems

john from Ontario · Nov 2, 2017

I have an Allis B with Mag. and hand start. It misses on #4 cylinder, but I found that if I partially close off the choke it will run on all 4 cylinders. I have replaced wires and plugs, checked for spark, got good gas flow out of the carb, and cleaned the carb (didn't do much disassembly). The compression is very low on all cylinders, about 40 psi. The engine does not burn oil or smoke and there don't appear to be any broken valve springs. I don't mind doing necessary repairs, just want to zero in on what might be wrong. Thanks for your help. You guys have helped me a lot over the years.

Dick L · Nov 2, 2017

I would run Sea Foam in both crankcase and gas tank as stated on the can. If after a few months of hard running with seafoam and no change It most likely needs a valve grind at the least.

dahlin · Nov 3, 2017

Did you replace the wires with solid copper graphite will not work well with a mag, also check at night for spark jumping to the oil filter been there. Randy

steve(ill) · Nov 4, 2017

Closing off the choke cuts the air and increases the fuel ratio to air... You carburetor is probably a lot of the cause... Also 40 psi is VERY LOW.. Barely enough to keep it running......... Do the sea foam as Dick said and drag something around for a few hours and see if things seal up better to get more PSI.

Allis B problems

john from Ontario

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Dick L

Well-known Member

dahlin

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steve(ill)

Well-known Member

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