Air compressor motor cutting out: bad pilot valve?

10 years 8 months ago #356 by ericconn
Air compressor motor cutting out: bad pilot valve? was created by ericconn
Hi, thanks for any help you can give. I have an Emglo K5HGA-17P with a 5HP Honda GX140 QX motor and KU pump. I rebuilt the carburetor on it, but it won't stay running once the tank gets pressure. I have an older style throttle control that fires a piston out that hits an arm connected to the throttle lever. It doesn't connect right to the throttle lever like the one listed for the K5HGA-17P on here.

It seems like the throttle control gets activated before the motor has time to warm up, and even before the tank really reaches max pressure. I was able to start the motor enough to get some pressure in the tank, and when I bleed air via the pilot valve, it makes the throttle control piston shoot out. Is this supposed to happen, or do I possibly need a new pilot valve? Again, thanks for any help. I know that if I get the compressor back up and running I'll be buying a new valve/gasket kit for the KU pump from you guys.

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10 years 8 months ago #357 by MTR-Admin
Replied by MTR-Admin on topic Air compressor motor cutting out: bad pilot valve?
I think you could have a defective Pilot Valve, yes. It's pretty typical for this to happen, it seems it's firing off sooner than it should. It should kick into "high gear" until it hits max PSI (which is 125 PSI), then idle down, then kick back up at 95 PSI or so.

Most of the time this is caused by dirt or debris inside the Pilot Valve, I would take the top off (there are four brass nuts you can remove) and take the Spring and S.S. Ball out, many times condensation build-up or debris won't allow the S.S. Ball to seat properly, so it won't actuate the throttle control mechanism like it should.
These Valves are adjustable, but are notoriously fickle. If you attempt to clean it, adjust it and it still won't operate like it should, I would just replace the Pilot Valve.

I'll do some additional virtual trouble shooting and get back to you with some more info, as well.

Thanks for the post!
- MTR

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10 years 8 months ago #359 by ericconn
Replied by ericconn on topic Air compressor motor cutting out: bad pilot valve?
Great, thanks a lot for the reply. I will take the pilot valve off when I have a chance and see what it looks like inside.

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10 years 8 months ago #360 by MTR-Admin
Replied by MTR-Admin on topic Air compressor motor cutting out: bad pilot valve?
Also, The GX140 is not the correct engine for the K5HGA models, Emglo uses either a 5 HP Honda or the 5.5 HP Honda (GX160).

Either way, the pilot valve is most likely the culprit. Also be sure to check the RPM’s of the engine as well. High idle is 3400 and the low idle is 2200.
- MTR

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