If the compressor is empty it fills up with air just fine. Once it begins to drop in pressure (after being used) the motor clicks on and it putters and sounds as if it is barely running(clanking). I empty all the air from the tanks by loosing the valve on bottom and it fires right up and sounds great. It then refills just fine.

STOP. What pressure does the gauge show? If it's higher than it should be, drain the tank and replace the pressure switch. If it's not unusually high, then replace the pressure relief valve.

DO NOT let that compressor run at too high air pressure! A burst air compressor is a TERRIFIC bomb, and can kill you before you know what happened!

All compressors dump a little air when they shut off, it's the air in the pump head and discharge tube. This bleed off should only last two to three seconds. If this pressure isn't bled off the motor won't be able to restart when the pressure drops in the tank becuase there will be too much pressure in the pump head for it to start turning again. If you have a longer bleed off or if the motor is struggling to restart most likely you have a stuck or broke check valve. It's the piece where the discharge tube connects to the tank. It's designed to let air into the tank but not back out so the pressure valve can bleed off the air in the pump. On rare occasions you can remove it and clean it out but usually they have to be replaced. You would need Makita Part Number 409004-E.

Hi, the problem is with the contactors on the cut-out side of the pressure switch i would recommend getting a new switch the other set of contactors most always fail soon after. What type of compressor do you have and how old is it? have you tried cleaning the contactors with a wire brush? (if it is a old compressor make sure there are no capacitors on the motor/motors that are holding a charge before any repairs or service)
please let me know if i can help further.

If it is a new unit, my guess is that it is still under warranty. If you go looking around too much you could void the warranty, and the truth of the matter is that it could be a defect. I would suggest contacting the store that you purchased it at.The may just give you a replacement.

It's trying to come on too soon. 60 PSI is too much pressure for it to run. Reset the pressure switch to kick in around 40 PSI. That will do it.

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needs valves

The start valve gives your motor a running start before the motor begins to load as the pressure increases from an empty tank. The motor strain is more profound when there is pressure in the tank. If you plug the valve, the motor will instantly encounter a heavy load because it has to force air into a partially filled tank. This extra load without the valve will shorten the life of the capacitors and motor windings. There could be two problems with your unit that can revealed by test. What actually closes the valve is a certain volume of air produced by the compressor. If the compressor is not pumping to full efficiency or there are leaks in the discharge hose the valve will not close. Or the valve is faulty. With an empty tank, plug the valve and run compressor and test airline for leaks with soapy water. If no leaks, empty tank of air and restart compressor and take note of the amount of time it takes to fill the tanks to shut off. If it takes an unusually long time to fill, then the compressor probably has valve problems causing low air volume. If the compressor fills to shut off in a short time frame as compared to a similar model then replace the valve. Leaking valves in the head will also cause the pump and discharge tube to run very hot. Parts are available at www.toolpartsdirect.com Good luck with your repair.

TO ME IT SOUNDS LIKE YOUR BIGGEST PROBLEM IS THE BELT. ITS INSIDE AND SURE ITS COLD BUT PROBABLY NOT THAT COLD. SPRAY CARB OR BRAKE CLEANER IN IT AND MIX WITH CHEAP OIL, RUN FOR SHORT PERIOD AND DRAIN. NOW PUT YOUR GOOD STUFF IN. VOLTAGE DROP CAN BE UP TO 10 V. READ VOLTAGE WHEN OFF AND WATCH IT WHEN IT COMES ON. MORE INTERESTED IN THE GAUGE OF POWER CORD. 15 AMPS ISNT ALOT AND A SHORT 12 GAUGE CORD SHOULD BE FINE. AMPS WILL PROBABLY SPIKE UP TO 40-50 DURING START-UP. THE AIR PRESSURE PUSHS ON A DIAPHRAGM WHICH LIFTS A SHAFT THAT MOVES THE POINTS BACK AND FORTH. YOU CAN WATCH THE POINTS OPEN AND CLOSE WHILE WATCHING THE AIR GAUGE. BELT SHOULD HAVE 1/2" DEFLECTION.

The piston in the motor has a larger "problem" bucking up against the 100 PSI of backpressure already in the tank. Thus, the larger amperage required to start the compressor motor when air is in the tank. Does the compressor motor have a starter capacitor? Perhaps the capacitor has failed...

Check the reset button on the motor to see if it tripped. The motor may be overheating. Some motors have an internal breaker and they have to cool off before they restart. Also check the pressure switch. Move the switch back and forth ( on and off ) and listen for a click. If it doesn't click with low to no air pressure then the switch is bad.