Mastercraft 8 gallon Air compressor, model: 58-7914- Compressor will not start

by RickG
(Timmins, Ontario, CANADA)

I have a fairly new compressor that will not turn on. When you turn the switch to the ON position, the compressor motor seems to hummm and then will eventually trip the circuit breaker. I've completely emptied the compressed air reservoir so there is no air in the system at all. The Compressor is a Mastercraft 8 gallon Air compressor, model: 58-7914-8

Any help woul help. I lost my receipt and they want to charge me for sedning it out to get repaired. The unit looks as though we just took it out of the box.

Thanks.

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Bill says....

Rick, are you sure the power is clean and enough amperage? Don't use an extension cord.

It sounds, based on what you are saying, that the motor isn't getting enough juice to start, and that could be a too long cord, too many other items pulling power from the compressor circuit, or it might be the start capacitor.

Bill




Comments for
Mastercraft 8 gallon Air compressor, model: 58-7914- Compressor will not start

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Apr 13, 2012
 Mastercraft 8gal
by: Anonymous

Thanks Rick,
That sounds like a possiblility. Bill referred me to the duty cycle info. Mastercraft does not give the information anywhere that I can find. But I did the initial break in run which was 30 min. At that point it worked fine and it was not under any load as no hose was attached. But then blowing air should not create a lot of load, it's just that when you blow continuously for a few minutes there is no cool down time. But we are talking 5 min. to at the most 10 min and the second time was no where near 10 min.

Used it yesterday to clean up my chain saw whan I was changing chains but was careful not to let it run too long after the tank ran out and started pumping again. Not real convenient.

I have an old and cheaper Job Mate that I have a hard time getting higher levels of pressure from or starting nuts with an air ratchet. Yet I never remember it having any problem when I was just cleaning up an object using air pressure.

Wish I was more of a mechanic as I really hate taking stuff like this apart. If I can fix it with wood I'm fine !! BUt I may have to tackle it. Just wish I knew how to get a service manual with good diagrams.

This Compressor was supposed to replace the Job Mate as I believed the Mastercraft were usually better quality. I guess I also hoped if it had been through a rebuild repair to put it back on the market, it would have been well checked out, but this could have been wishfull thinking.

Thanks for your input gentlemen !!

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You are most welcome, speaking for myself and Rick.

As to one brand being better than the other, it would not surprise me if both were made in the same factory in... you know where!

See the Troubleshooting section for reasons why an air compressor will run and not build pressure.

B.

P.S. I hope, with the M.C. issue, that you are not using an extension cord? If so, that could be the root of the problem.

B.
Apr 11, 2012
 Mastercraft Air Compressor
by: Rick

I took the entire motor apart and found the the actual piston was seezing. With the "head" off the piston, I was able to free the piston and put the unit back together. I added compressor oil to the top of the piston to help it out. It seems fine before winter, haven't used it since. My opinion, this specific model from Mastercraft is not very reliable. I would not recommend purchasing this compressor unless they change its warranty to life time. I also have a Campbell Hausfeld from Canadian Tire and I've never had an issue with it.
Apr 10, 2012
 Mastercraft 8-gal 58-7914-8
by: Bob

I bought a rebuilt unit with a 60 day warranty. Has worked well with my finish nailer. I have had problems twice while cleaning something with air. It you are blowing steady for 4 or 5 min the motor will lung down and cease. The top gets really hot. It I let IT cool down it has started so far. UseD it on the weekend stapling underlay on a floor and worked fine. Tried to clean the duct from a loovered metal door today and it ceased. Did teh same thing a week or so ago when I was trying to clean some vacum filters.

Any idea what is going on ?? I've had it just over 3 months now but only use it occasionally.
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See the page on this website about duty cycle. If you are running your compressor too long at one time, you are wearing it out.
Sep 02, 2011
 Compressor motor won't start just humming sound when turned on
by: Anonymous

I have the same problem. I removed the plastic housing cover on the motor and found out that one wire was cut from the capacitor?(not sure what it's called) I spliced the wire and attached it to the screw where it was cut off. Start the compressor and it works.

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