Won't build past 40 psi and funny smell

by walt
(darlington, sc)

Pressure will not build past about 40 psi and has a funny smell. Motor continues to run. 21 gallon central pneumatic compressor.

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Jan 27, 2016
Pressure build and compressor smell
by: Bill

When you say "Is it likely that this could be the root of my problem?"

What is "this" Walt? That you leave the compressor powered up? No that should not be an issue, though, if you have a system leak, the compressor will cycle on and off as the tank pressure changes.

Otherwise, please provide a bit more info.

Maybe get the pump kit installed and test first?

Jan 27, 2016
pressure build problem
by: walt

Once I entered the model # I saw the post about the Campbell Housefield kit that fits my unit. I figured for $16 including shipping I would give it a shot. If that doesn't work I'll probably just follow the economics section and get a new one.

I had left this on for a few days and would hear it kick on occasionally as it should.

Is it likely that this could be the root of my problem?


Jan 26, 2016
94667 funny smell etc.
by: Bill

Debris in the pump?

That sure sounds like you've got a valve or gasket issue, Walt.

If the gasket between low pressure and high pressure side lets go, which often happens when there is pressure in the tank to work against and it blows open, the symptoms you refer to could occur.

A valve plate and gasket kit wouldn't be remiss.

The bad smell thing... is there air coming out of the oil fill tube while the compressor is running? If so, piston seals may be part of the problem as well.

Jan 26, 2016
Troubleshooting ??
by: Walt

I have generally gone through the checks in the documents. Power hasn't been a problem in the past and I haven't changed the outlet that it is plugged into so I'm going to rule this one out for now. There is no leaking that I can hear when I power the unit off, so I'm going to rule that out also.

Not really sure how to check the valves although I followed a drawing I saw on the sight and removed the head to expose the reed valve. It appeared to be OK, but there was some debris on it and the piston below.

I'll see if I can find a manual online to locate the intake filter and check that too.

Probably more interesting was the economics section which pointed out what I thought the resolution might be. I guess I posted the question hoping I might find something simple that I could do myself.

So I'll check the other valves/filters that I can, but otherwise probably just get another one.

BTW-there was some oil (not much) on the head when I removed the plastic shroud.

Model # 94667; 3 hp; 21 gallon.


Jan 26, 2016
Compressor 40 psi and funny smell
by: Bill

What did you find when you did the checks referred to in the troubleshooting page about air compressors that won't build pressure, Walt?

Update us with that information as a comment here, and we'll be pleased to help further.

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