921.166390 stopped building pressure

by Dave


Today while filling a tire the compressor stopped building pressure above 30psi

I read all of the other related posts and checked the filter and can't seem to find any leaks anywhere however I have noticed while it is running there is air pressure coming out of the vents in the oil filler cap and from where the air filter is at.

I'm kind of surprised. it's a 2007 model but only has about 5hrs use on it.

Comments for 921.166390 stopped building pressure

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Sep 13, 2015
Low pressure
by: Doug in s.d.ca

This came up all at once as opposed to gradually, right?

If, in fact, there are no external leaks, then almost certainly you lost one or more reed valves. You'll have to pull the head to see if that's the case.

You may or may not want to order a new head gasket ahead of time - it could actually BE the problem, and you'll need one unless you decide to junk it.

Good luck.

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