The compressor takes a non-detergent motor oil. It is also labeled compressor or pressure washer oil. The detergents in regular motor oil are not necessary and will foam.
I have not tried running carb cleaner mixed with the gas but it should not hurt to try it. There is a product called Seafoam that works well used this way.

30 weight non detergent is the standard oil. We also suggest compressor oil but any 30 ND will work and we have never seen a failure from it.
The synthetics are nice as you change it less. Stuff like the Ingersoll Rand T 30 Select.

I have a Sears Twin Cylinder Tank Type compressor for paint spraying. The vertical compressor is cast iron. I have had it for over 20 years and never had a problem with it. I have used 10W-30 Detergent oil in it as recommended in the Operating Instructions. It specifically says, "Always use 10W-30 detergent motor oil". I use this compressor almost every week for operating air tools, or just cleaning parts with compressed air. It has been the most reliable power tool I have ever owned. I have to drain the water out of the tank a couple of times a year, and usually change the oil every 2nd or 3rd year. I found it interesting the newer compressor described above requires non-detergent oil. Charles Ranheim

There is really no need to use a detergent oil. The detergents break down combustion by products which are not present in a compressor pump. With that much use, you should be draining the tank at least once a week, especially when spraying. Paint is not very tolerant of contaminants.

canguy
You are correct about saying I should drain the water more often. When I get around draining it, it comes out mixed with some oil, but I never had to add oil between changes. I have not used it to spray paint in many years, but have sprayed undercoat with it. My main uses are blowing out parts, and air tools. It has a tank operating pressure of 120 to 150psi. I generally set my line pressure at 100psi.
As far as the oil goes, it is easier to find detergent than non-detergent. But, for some reason, the operation manual specifies detergent oil even though non-detergent oil was more plentiful when I bought the compressor. Thanks for your comments. Charles Ranheim

Charles usually detergent oil creates more carbon which can foul the valves. We sell 29 brands and all suggest non detergent.
While you are having good life with your compressor I don't think you are using it really hard. Heat causes the carbon build up and high use causes the extra heat.
As stated the tank should be drained more often. Manufacturers suggest after each use. This will keep the tank from rusting too soon and after 20 yeard I would sound the bottom of the tank with the ball of a hammer to check for soft spots. Might save you one day.

I once had a smaller compressor tank spring a leak at the bottom. That one used to have rusty water drain out. This compressor puts out clear water except for some oil that is mixed with it. As I said before, the manufacturer specifically said to use a detergent motor oil. Perhaps the newer compressors use different materials than the older ones like mine, and run better on non-detergent oil. There are times when the air coming out of the hose smells hot because I have used it for such a long time. Having access to compressed air makes things easier for me. I even use it to blow the leaves out of my gutters using a 15 foot extension pipe to reach the second floor area while standing on the ground. It is a great tool. Based on its longevity, I will probably continue using the same oil I have been using since the day one. Again, thanks for your comments. I always appreciate hearing all sides of a topic. Take care, Charles Ranheim

I have a air compressor model number 919174350, 2hp double cylinder 12
> gallon horizontalcompressor 7.8scfm 40psi9.6 CFM 272
> ltr/min, and need to know how much oil it needs , it was a gift
the little window is not clear anymore.
thanks

You can pull the sight glass and clean it.
Most small machines use about 1/3 qt of oil.
Detergent oil does cause carbon build up in air compressors and can foam which is bad for a splash lube machine no matter what the owners manual states.

I just bought a little 4.3 twin tank compressor for nailing and it uses 30 sae oil. I use it a couple times a month. How often should you change your compressors oil?

I'd never recommend that someone use an oil other than what is recommended by the compressor manufacturer, but the whole non-detergent oil only thing has always seemed counter-intuitive to me. If the detergents can cause foaming in a relatively slow turning (in comparison) compressor pump, then where's the foaming in a splash-lubed small engine that's whirring along at two or three or four times the rpm using the same detergent-type oil? And if the detergent oil can cause carbon buildup, then don't those same detergents serve to dissolve and keep the carbon deposits in suspension?

Also, take a peek under the hood of a semi-tractor. The reciprocating piston air compressor pump that serves to feed air for the braking system is plumbed into the engine oil supply. There aren't any issues at all with foaming, carbon buildup, or longevity with those pumps.

Finally, why do the suppliers often charge more for a non-detergent oil? You'd think it would cost less.....

;-)

The detergent is needed to break down the combustion by products which are not present in a compressor pump. Also remember that engines turn much faster and operate at much higher temperatures.
That big rig pump is lubed under pressure, not splash like the one in the shop.
ND oil is produced in much smaller quantities so production costs are higher.