Compressor trouble shooting

Got a 12 gal Sears oilless compressor from a friend of mine. And the compressor continues to give me trouble.
It starts cold, runs up pressure and then won't restart. I asked friend for help. He tried it, a couple times, the unloader is a bit balky. Just cycle it.
Still no joy. He replaced the unloader valve, which was really above and beyond the needs of friendship.
Tonight I went to use it, first time after the unloader replacement. Starts cold, and ran up to 120 PSI. I figured I only needed 100 for the job, pressurizing a water fire extinguisher.
I could hear the unloader hiss when it satisfied. But the compressor won't restart, even if I bleed it down to zero. Gives me a burning smell that makes me want to open the door and let the stink out.
It's not near a power socket I can reach, so I've got it plugged into a 16 ga cord, into a socket. Says it draws 16 amps. I'm wondering if it's not getting enough voltage (have to check next time). Or if the motor and piston need lubrication.
Any ideas how to troubleshoot? I sure can use a compressor in the summer for air tools. If it worked....
--
.
Christopher A. Young
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On Thu, 20 Nov 2014 19:54:26 -0500, Stormin Mormon

I have a similar compressor and it really needs the full 120v to start reliably. Extension cords are an "iffy" thing. Of course you could just have a bad start capacitor or a bad centrifugal switch. I would drag it over to a known good receptacle to break the tie but don't screw around with this. Smoking is not a good thing. If it doesn't start right away, turn it off.
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On 11/20/2014 9:05 PM, snipped-for-privacy@aol.com wrote:

Motor start cap. I'd not thought of that.
Maybe in the morning, I'll see if there is a start cap.
And put on a new plug to replace the corroded one. And try it direct to the socket.
Thank you. And yes, smoking is not good. That's why I pulled the plug. Friends don't let compressors smoke.
- . Christopher A. Young Learn about Jesus www.lds.org .
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On Thursday, November 20, 2014 9:05:56 PM UTC-5, snipped-for-privacy@aol.com wrote:

+1
I'd never use a 16g extension cord on that size motor load. Also, how long is the extension? I have an electric power washer that a friend gave me and I always had problems with it tripping the breaker, over heating and shutting off, etc. Until I finally bought a 10g extension cord. Works fine ever since. If it's at the point it's making burning smells, it may be kaput.
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On 11/21/2014 7:01 AM, trader_4 wrote:

Hope I didn't kaput it over some thing as simple as this.
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.

+1
Mark
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On Thu, 20 Nov 2014 19:54:26 -0500, Stormin Mormon

I thought you were unable to shoot the compressor because you were a lousy shot. I was going to suggest target practice, but never mind.
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On 11/20/2014 9:06 PM, Gordon Shumway wrote:

How'd you know? I am a lousy shot. One of the reasons I turned out like I did.
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I woulda though that if it was a bad start capacitor then it wouldn't start the first time either.
Do you have an infra red thermometer? I'm wondering if the problem is that the piston is expanding in the cylinder and causing excessive friction until the piston and cylinder cool down. Once everything cools down again, if it seems to work properly only until the piston heats up again, that may be the issue. If you can measure the temperature of the cylinder you may be able to compare that with similar oilless compressors that are working properly.
But definitely, when using a compressor and air tools, it's best to keep the extension cord to the compressor as short as possible and get the compressed air to where it's needed with a longer air line instead.
--
nestork


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On 11/21/2014 1:43 AM, nestork wrote:

I've had a couple people go with "needs more power" opinion, so I'll try that next. See if I can get the compressor close enough to put it directly into the wall socket, and take the 50 foot 16 gauge cord out of the picture.
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wrote:

I agree. If the FLA of this motor is 16a, he is dropping almost 8 volts right there., just in the cord. The NEC would let him drop another 5% at the receptacle face plus any loss in bad connectors. Then you say the start current is more like 40a and (250%of FLA) you see why this is a problem. My compressor would not start plugged directly into a 20a circuit, simply because we were 150' or so from the panel (out in the parking lot). I rolled it up to the building and it worked fine. Fortunately we were able to come up with 150' of hose so we could work
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On 11/21/2014 3:21 PM, snipped-for-privacy@aol.com wrote:

Thanks for the field report. I'm going to try a direct run to the socket, and may also upgrade to a Leviton, taking out whatever trailer quality electrical socket (receptacle) is here. Don't expect to need the compressor till much warmer weather, so my update may be several weeks from now.
- . Christopher A. Young Learn about Jesus www.lds.org .
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Oren posted for all of us...

He's been told that several times but did it make a difference? That is for you and the other posters to answer. I can't figure out whether Stumped is stoop ed or a troll. That is another decision that has to be made. I feel sorry for people looking for help and follow his blatherings. "I read it on the Interweb so it must be rite"
--
Tekkie

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