Used air compressor

[trainmaster]

Folks, I bought a used gas engine air compressor. It had been mounted outside on a work truck and then sat a couple of years outside. Should I get the tank pressure tested? Where would I do that? My welding supplier said he doesn"t know. In addition, it has an 8hp B & S engine. I have gas, air, and spark. When it fires, it fires backwards out the carb. Is there a way to adjust the timing on this thing? Is the only possible "adjustment" a damaged Woodruff key holding the flywheel in position? Thanks in advance, Dan.

 

[Anonymous-0]

If the flywheel key is damaged, it won't run, replace that and set your coil air gap, A ceral box cardboard will work for spacing, the correct gap escapes me. As for the tank, I would drain it and see if any water comes out. I have only seen tanks rust out the bottom from water sitting in them. That can normally be patched. I would think the rest of th tank would be ok.

 

[Anonymous-0]

Open the water drain on the bottom and see if any water comes out. Visually inspect the tank and then if it seems OK, take a small hammer and tap on the bottom of the tank. That will give you a good idea if the tank has any weak spots. The safest way to test the tank is to fill it with water and then use a porta-power pump or even a grease gun to pressure it up to at least 150 PSI or about 50 lbs. more than the working pressure. You'll need to install a gauge to read the pressure. They make high pressure water pumps for testing but I doubt you'd ever find one. After testing, slowly release the pressure and dry the tank out with a heat gun or even a blow dryer to get rid of any moisture. Dave

 

[Anonymous-0]

Intake valve on the engine is sticky. First shoot some penetrating oil in the intake to see if you can get to the valve guide. If that doesn't work take the side cover off and work some penetrating oil in the guide.

The tank will show rusty water leaks out the bottom if it is shot with rust. It won't hold pressure over a long term if it is shot.

 

[JDseller]

Back firing through the carburetor on small motors is usually a intake valve problem. The spark timing is static on the flywheel with no adjustment. You either have a stuck , burnt, or slow closing intake valve. When the motor fires some of the gases are coming back out through the intake valve.
Check to see if you have compression. If you do then remove the carburetor and see if you can see the intake valve through the intake port. Watch it and see if it is moving correctly. If it is sticking it will close slowly. It is many times just s fast to remove the cylinder head. You can reuse the head gasket most of the time. Just use Copper Coat on it. You can then see what condition the cylinder walls and valves all at once. These Briggs and Stratton engines are not the best but are cheap and easy to fix.

 

[Anonymous-0]

Pressure vessels weakened from corrosion should never be patched. They can explode under pressure! If you are not sure about it's integrity, replace it.

 

[Anonymous-0]

If the engine is pretty bad, you could always put a Honda copy on for only a few hundred $$$. Dave

 

[John Harmon]

So: Some are saying to not trust the Tank and replace it and don't fool with the Engine,replace it! With all that what did you buy? Not much seems to me. I hope you didn't pay to haul away some one else's junk.

 

[Anonymous-0]

It might have a really good compressor and didn't cost very much. If it was just sitting outside, the tank might be fine. The engine might just need minor work as well. I was just suggesting that it might be better to replace the engine if it needs a lot of work. Dave

 

[GordoSD]

Two words....boat anchor

 

[Flurette Farm]

135 fan is right. Do a hydro test on it with water. I'd test it at 2 times working pressure. If you are using 120 test at 240. Design is probably at least 2.5 times working pressure. Water won't kill you but air will. Be safe.

 

[trainmaster]

Thank you for your replies. I will see what I can do to pressure test it. As for the engine, I will check the intake valve. And yes, with me money is always an issue, so I had to buy something cheap and hope I can fix it. Thanks again, Dan.

 

[52 M37]

Hydro-testing the tank is a good idea.
The test pressure should be 1.5 times MAWP for tanks built prior to 1999 and 1.3 times the MAWP for newer tanks. If the tank is not stamped with the MAWP see if the relief valve has a set-pressure stamped on it and use that as the MAWP. Watch for any bulging as you bring it up to pressure. A certified gauge is also a very good idea. If the test pressure is 150psig a gauge that reads to 200 psig will work the best.

Do not go to 2 or 2.5 times the working pressure, you could ruin the tank.