20 Most Recent Craftsman 1 Hp, 4 Gal. Air Compressor Questions & Answers

The manual for the compressor will tell you how. If you do not have the manual try here: Craftsman 16639 1 HP 7 Gal Portable Air Compressor Manuals

my ace air compressor which is 26 gallon 5 hp will not get over 60psi what is wrong with it please?

Drain the air all the way off and see if that helps. If it does, you may want to replace the check valve on the top of the tank.

This is a statement, not a question. How could anyone respond with a useful answer?

The pressure switch probably has a burned contact.

The most likely problem is a burned out "run capacitor" on the motor. If you continue to try to run your compressor in this condition it will burn out the "starting capacitor" and/or motor as well.
It's also possible that you have a bad start up pressure relief valve, this valve will be between the compressor and the tank. If this valve is working properly you should hear a hiss of air as the compressor motor shuts off.
A reasonable motor repair shop should be able to replace the run capacitor for $20-$50 plus inflation, depending on your area.
If you need to test the start up pressure relief valve, you need to take it loose at the compressor or tank. Just loosening the line may not work depending on the style used. Note: sometimes just taking this loose to test it causes you to have to replace the valve.

Check to make sure you have the right volts comeing to your compressor 120 volt any thing less then 10% can make this happen.Also if your compressor is really old it could be trying to stick aand needs taking apart and cleaned

sounds like reed valves are bad,sometimes you can take the reed valves and flip them over for short fix,best to put new one in unit.

Could be the air release at the bottom of the tank is open.
It's used to drain all the moisture out after each use.

Clean the tube and where it goes in to the head and put jb weld to hold it in.

You have a broken reed valve(s) in the pump. Without knowing your model number I don't know if it's repairable nor can I recommend a replacement part. If the head is removable, take it off and check the valve plate under it. There should be two or more reeds on each side. If they are chipped or broken or warped from heat they won't seal the valve holes and the system can't build pressure.

Hi, ALL WAYS UNPLUG THE POWER.
The humming may be the motor itself, or a deficient capacitor.
I suggest taking several pictures of the suspected parts, before anyattempts to fix/replace them.

1- 90% of the time, the most frequent problem is the "starterCapacitor" going bad. It is a metal uncased capacitor, normally attachedto the electric motor. They have a sears number to reorder, and you can replaceit yourself, just unplugging the connecting wires and plug them to the new one.Any electronic place that sells parts may be able to sell you a replacementCapacitor cheaper than Sears.

2- It could be the electric motor itself going bad, if you have low voltage. Ifinstead of 110V you normally have 92Volts, after many times, it burns thewinding coils. Try this: UNPLUG THE POWER AND KEEP THE STARTERSWITCH OFF. Spin the electric motor by hand (you can do it rotating theBELT) about 10 to 40 degrees, this will reposition the coils. MAKING SURETHE SWITCH IS OFF, PLUG THE POWER, and THEN TURN THE SWITCH ON FOR 5SECONDS, if it won't start, turns it off. When this procedure worksmaking the motor to start, but fails again, and every time you use thisprocedure Works, you have a defective coil going bad, "meaning" thatthe electric motor have to be replaced. If this procedure works, you may beable to avoid replacing the motor till the time that it does not work anymore.

3- Also, it may be that just at that particular day, your electric grid has lowvoltage due to high demand, but next day is Okay. Try next day, or when thehigh demand is fix.