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Craftsman Air Compressor Won’t Keep Running, Stalls, Cuts Off – Solutions & Causes

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Craftsman 5hp 20 Gallon briggs and stratton gas powered belt driven air compressor stalls when pressure builds up?

by john piper
(palm bay, fl, USA)

I have a craftsman 5hp Briggs and Stratton gas powered belt driven air compressor that quits/stalls running when the pressure builds up.

There are 2 valves that I can manually bleed the air from.

Craftsman 5hp Briggs And Stratton Gas Powered Belt Driven Air Compressor Stalls When Pressure Builds Up 21605689
Craftsman 5hp Briggs And Stratton Gas Powered Belt Driven Air Compressor Stalls When Pressure Builds Up 21605689
Craftsman 5hp Briggs And Stratton Gas Powered Belt Driven Air Compressor Stalls When Pressure Builds Up 21605690
Craftsman 5hp Briggs And Stratton Gas Powered Belt Driven Air Compressor Stalls When Pressure Builds Up 21605690

One is fancy w/ some sort of diaphragm coming into it before the valve w/ air supplied from the comp. and the other side of it goes to linkage on the motor which appears to adjusts the governor as needed.

If i leave the leaver on top flipped/tripped were it leaks a little the motor will keep running fine and build up air but once i close it and the air press. gets high the motor instantly stops like its locked up or been turning off like an electric one. the other valve is just a typical high pressure blow off type located just before the hose connector. the motor runs great w/ good compression and the compressor builds up pressure quickly which is why im thinking its the fancy pressure regulator switch…any help will be greatly appreciated

John, I don’t have a gas driven compressor, so I hope that folks out there that do will comment and correct any mistakes I make.

It sounds to me as though your unloader, which is linked to the throttle, needs adjustment. When the air pressure in the tank reaches the normal cut out pressure level, instead of a pressure switch turning the motor off, as it does with an electrically driven compressor motor, it unloads the motor and throttles back on the fuel so the compressor motor slows down but keeps running.

When the pressure in the tank reaches the low pressure cut in, the pressure switch toggles the unloader which adjusts the throttle to increase the revs to speed up the motor, allowing it to handle the increased load as the pump starts pumping air into the tank.

I hope someone has a manual or a how-to to help you adjust this mechanism, John. I have not worked on them myself.

Craftsman air compressor cutting off at 50 PSI

My 921.164710 cutting off at 50psi even though I already replaced switch and adjusted it?

by Jon Mitchell

Craftsman 921.164710 Air Compressor
Craftsman 921.164710 Air Compressor

I have the 921.164710 and it was shutting off at 50psi.

I adjusted the cutout and it didn’t change anything.

I replaced the switch for $75 and it’s still cutting off at 50psi, even after adjusting the cut out again.

Please someone have some insight on this.



Cut out?
by: Doug in s.d.ca

What is cutting out?

Is it bogging down?

What happens if you run down the air pressure after it stops? Will it restart on its own in a predictable way (i.e., the same pressure?)


Clarifying condition
by: Mike P in Vegas

Is it possible that it’s a coincidence that the compressor is shutting-off — due to an air compressor thermal overload switch, over-heating condition — which coincides with the tank’s capacity to hold roughly 50 psi?

Try this: with the tank completely EMPTY of all air/pressure, run the compressor and see what pressure you hit when it cuts off. Time this as well, and try to assess the temperature of the compressor motor (without burning your hand of course).

Repeat this test using a partially-charged tank/reservoir.

See if your times (for auto cut-off) are the same, and/or if this confirms, it’s a 50psi rating consistency.


Same model, same problem (I think)
by: Kenny

I believe that I am having the same issue and that Mike is correct that it is just a coincidence that the unit is cutting out at 50 psi and that it is probably thermal overload.

Mine cuts out @ 50-60 psi and cylinder head, outlet tube, check valve, and relief tube are scorching hot yet motor housing below valve plate is not.

If I turn it off, unplug it, and let it cool for 10 minutes, it will start back up until it overheats again.

I’ve tested the wall outlet and capacitors, both are good.

I’ve replaced the pressure switch, the check valve (accidentally broke it), and valve plate/gaskets but still cutting out.

The piston and cylinder show no signs of damage that I can see.

Don’t know what else to check at this point, any suggestions?

Craftsman air compressor motor shuts off after 20 seconds

by Mike

I have a Craftsman oil-less compressor, 6hp 33 gallon with an AO Safety motor. It runs for 20 seconds and then trips my surge protector.

I am running motor only, the piston and such are not hooked up.

I tried to replace the capacitors. Cheap fix..it’s not them. The motor runs the same even with the capacitors NOT plugged in.

Everything is clean, no broken or burned wires.

I did notice a round (sensor or pick-up of some sort?), quarter size component that is attached to the back of the motor body that gets pretty hot to the touch but I don’t know if its replaceable or what it’s true function is.

Any ideas?


Mike, if it’s tripping the surge protector ( is it in a power bar, if not, where is the surge protector) then it’s pulling more amps than the circuit can handle.

It’s not entirely clear from your comment (at least to me) if it’s tripping out after 20 seconds when it’s not coupled to any load at all?

Regardless, to me it sounds like an electrical fault, and the motor is the likely culprit.

Often, this symptom is caused by a weak capacitor, but you changed yours, with those of similar rating I’m sure, so that points back to the motor.

If you are using a power bar with a power bar, please don’t. The power bar itself might be the problem.

Craftsman 106.153784 Sears air compressor stalls

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.

Sears - Craftsman 2 HP air compressor - newer version
Sears – Craftsman 2 HP air compressor – newer version

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

Thanks Stan


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.

Craftsman 106.153784 Air Compressor squeaks and shuts off

by Daniel Gomez

Model # 106.153784 sears compressor oil driven will power on for about a minute pressure only reaches 30psi compressor rated at 150psi.

After a minute I hear a loud squeaking sound coming from the flywheel/pump area then it just stops while squeaking.


Daniel… check the belt tension and alignment first please. That may not be the problem, but lets eliminate that as the source.

What I surmise from your post is that as the pressure in the tank builds, the pump has to work harder to get air into the tank. As a result, the motor has to work harder too.

If the pump bogs down to the point where the motor cannot cycle it, the motor will overheat and go off on safety.

With the tank empty, remove, inspect / clean the tank check valve. Again, this may not be the cause of the issue, but lets get it out of the way.

Assuming that it is not the motor that is squeaking, that suggesting that the motor itself is the problem, I am guessing that you may have a valve problem in the pump, that’s back-loading the pump and overloading the motor.

If you run the compressor with the line from the pump head off, I suspect it will run with no issues, right?

After you put the line back on, pull the pump intake filter and feel if air is being pulled in strongly as the compressor runs.

If so, that would suggest that the issue is the high pressure valve, and that means a pump tear down and valve replacement.


It was the belt tension
by: Daniel

It ended being the belt tension. I unbolted the motor and slid it as far to the side as possible, making the belt tighter.

Thanks for taking the time to help me. God bless.
You are welcome.


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By Bill Wade

About Air Compressors has been helping folks with their Air Compressor Problems since 2002 online. We're a community of DIY and Compressed Air professionals who are keen to support everyone across the globe with their air compressor issues and troubleshooting. Whether you're trying to identify an old air compressor, or troubleshoot an error code on a sophisticated new industrial air compressor - the community at About-Air-Compressors.com is here to help you

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