Air Compressor problem

I have a Craftsman Portable comp. 125 psi max when I turn the unit on it will start and run but the pressure on the gauge never gets above 25PSI and the compressor will run forever if I let it. I have taken the comp unit apart and everything seems fine the flutter valves aren't stuck and the rings are ok. I do feel air coming from the oil fill cap which I can understand that there would be some buildup in the oil tank. I have taken all the lines apart and teflon the connections. Any other ideas

 

Not too familiar with Craftsman air comp., but if you are not building pressure then the valves are possibly leaking. If there is pressure in the crankcase I am guessing you have a ring problem or a cracked piston. Some blowby is acceptable, but not that much. I am presuming that you have checked the intake to see that the filter is not stopped up??!!! Keep us posted.

 

Yes I have checked the filter, it is fine. On inspecting the piston I did not see any crack or ring problem.
Thanks
I will check the piston more closely. I might even replace it and the rings.

 

I also have a small craftsman 3 gallon compressor. It is just a year old and developed the same problem. Will not even get to 5 # of pressure. Completely disassembled: Piston and rings looked good, two reed valves looked good, check valve OK. I put it back together and started up with supply line unhooked and I can hold pressure back with finger over the discharge line. Do we both have the same problem???

 

Welcome to the forums, James. I'll try to help as well as Mike. On some compressors there is an unloader. It has a small ball bearing in the top of a compression looking fitting. If that ball bearing doesn't seat in the hole, it will never reach a working pressure. Both of you, while your compressors are running, run your hand carefully around all the fittings, lines, and valves. And as elementary as it is, make sure the drain petcock is closed completely. My guys will faithfully drain my compressors daily, but one of them forgets to close the valve and it never pressurizes until we close it.

 

i have a 15Gallon 4-5 hp Craftsman Aircompressor wheel barrow looking configuration. i was using it one day and it just suddenly died. now it wont start. my neighbor says that power is getting to the switch but no power after the switch. Is this an easy part to replace? or is there some fuse/circuit breaker in the switch that just needs replacing?

 

I have the exact problem with my 3yr old sears 1hp 5gal unit. Model 921.166360. The piston head and reed valves looked ok, but I noticed blow by from the 2 holes in the oil fill tube. I undid the flex hose from compressor to the tank and there seems to be plenty of air coming out.

At a loss.
Underneath the electrical box, connected to the copper tube there is a valve of some kind with a small pin extruding from it. It moves when the pump is cycled from off to on. However, it dosn't seem to touch the stop located about an 1/8th inch from it.

Any ideas? Thanks