I have a old Sears model 106.153784 2HP 220 Volt compressor and the motor stalls when it gets up to around 50-60 psi. Seems the pressure is backing up to the head. I cleaned the reed values and they seem alright but still have that problem, cleaned the spring valve in the line to the tank and that valve seems to work with no luck fixing the problem, says Stanley of San Jose, Ca.

 

New Sears / Craftsman 2 HP air compressor

New Sears / Craftsman 2 HP air compressor

 

Any help would be most appreciated. You think new reed springs would help?

Thanks Stan

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Hi Stan. Thanks for visiting and writing in.

I take it that the spring valve you refer to is what I would call the tank check valve?

You say that “the pressure is backing up to the head”. That is to be expected, as back pressure and the load on the motor increases as the pressure in the tank builds. Normally an air compressor is built to accommodate that.

When you say the motor stalls, are you saying that the motor shaft rotation slows to the point where it stops and the pump no longer cycles? If that’s the case, that’s a typical response if the motor isn’t getting enough power, or hasn’t the power to  overcome the load. Since the air compressor is built to have the motor overcome the increasing load from the tank pressure in normal operating conditions, then something else is the issue.

I suspect your compressor either has a failing capacitor which would curtail the available power to the motor as the compressor load builds, and that could cause the stall.

The issue may also be a problem motor though I would opt to check the capacitor first, as that could be the issue.

It could also be a  a mechanical problem with the compressor pump but again, the first thing to check would be the motor capacitors. So, start by testing the capacitor(s) and ensuring they are working properly. See the page on how to do so on this site, and then please post a comment with the results.

If you could add a photo or two of your compressor is would help us all.