Correct spark plug for UB propane

jnf · Nov 14, 2015

What is the correct spark plug and gap for a UB Special propane?

J.Wondergem · Nov 15, 2015

Autolite lists a 14 MM- 306, and if it's 18 mm - 373. I hopes this helps.

MMDEL · Nov 17, 2015

If you are going to use it and pull it you want the coldest plug you can find. I use AC "C81" in all the tractors I farm with. If they are just going to putts around then it can be a little hotter. Problem is the plug companies are discontinuing some of these cold numbers. Also I found that some of the late conversion charts converted a C81 to a much hotter number in their line. If you are working an LP tractor to it's fullest a hot plug will preignite the LP fuel. The gap on an LP engine should be .015 this is in your MM tractor manual. A wide gap in a higher compression LP engine will not fire under load. (Test this in a spark plug tester, the higher you increase the pressure the spark will fade and die.) The LP engine burns so clean you din't need to worry about a close gap fouling out.
MMDEL

jnf · Nov 19, 2015

Thanks. I was using too hot of plug. I simply was replacing with what was in it which may be why they weren't lasting.

Correct spark plug for UB propane

jnf

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J.Wondergem

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MMDEL

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jnf

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