Onan Microlite 2500 LP problems

[willbrackman]

I recently purchased a '95 30' Classic with a factory installed Onan Microlite 2500 genset that runs on LPG.

The spot where I have the trailer parked while I do my renovation work doesn't have AC power conveniently close at hand so I was firing up the genset whenever I needed power to run a vacuum or a small tool.

Everything was working fine until one day the genset sputtered and tried to die when I turned the vacuum on in the trailer (probably 1,000 watts). I tried it again with just a 3/8" electric drill and the same thing happened: the genset made a noise like it was starved for fuel and was in the process of dying. When I turned the drill off, the genset came back to life and ran fine.

I hooked up a different external generator to the external 120 volt A/C line and everything in the trailer works fine so I'm pretty confident that my problem is within the Onan genset, not internal to the trailer.

I tried re-setting the circuit breaker on the genset to no avail. In fact it's difficult to tell which is the off position and which is the on position. I tried it both ways without correcting the problem in either position.

Right now the genset will fire up and run just fine but it is not providing any A/C power to the trailer, no matter where I set the 25 amp circuit breaker on the side of the genset. It no longer is unsuccessfully trying to power the tool. I haven't tried a meter on the trailer electrical receptacles but I'm willing to bet that the genset is not providing any A/C power to the trailer.

Can anyone tell me what my problem is?

[withidl]

I've got a gasoline fueled Onan Microquiet 4000 on board my 2002 ASCL 31'; it now has over 913 hours on it. Your problem does not sound fuel related, unless you have insufficient LPG in the bottles to provide enough pressure/volume of LPG to fuel the genset when it throttles-up under load (are the LPG valves fully open?).

My 2001 Microquiet 4000 is computer controlled and in an abnormal shut-down the computer will blink a fault code (does yours do the same?). Last year the genset shut down with a fault code indicating "Over Frequency". This was due (after some grinding and gnashing of teeth) to failed "rotor slip ring brushes"; pulled the generator side apart, smoothed the slip rings, replaced the brushes and all is well.

The Onan engines seem to be very reliable. The gasoline fueled carburetors do get fouled unless “exercised” once a month, but yours is LPG fed so that’s why I don’t see an engine mechanical issue.

Hope some of the above helps.

[xrvr]

LP tanks must not be too low on fuel. Sometimes just above a quarter tank will cause starvation. jim

[willbrackman]

I wish my problem was LPG tank related but, alas, the tanks are full. And, as I said in my original post, the genset runs fine but is not producing any A/C power.

Thanks for all your help/ideas but I don't think we've solved this problem yet.

And, in response to "withidl", no, my genset is old enough that there are not any fault codes given.

BTW, this genset, despite being 16 years old, has only 160 hours on the hour meter.

[withidl]

Originally Posted by willbrackman

I wish my problem was LPG tank related but, alas, the tanks are full. And, as I said in my original post, the genset runs fine but is not producing any A/C power.

Thanks for all your help/ideas but I don't think we've solved this problem yet.

And, in response to "withidl", no, my genset is old enough that there are not any fault codes given.

BTW, this genset, despite being 16 years old, has only 160 hours on the hour meter.

It just occured to me that your problem may be in the engine govenor. My manual for the Onan Micorquiet 4000 states that over time the govenor spring may weaken and have to be replaced or repositioned to another mounting hole. It may also have rusted and broken. The spring is what throttles the engine when the rpm drops due to increased load. As the engine throttles up the govenor arm "fights" the springs pull to keep the engine from over reving. If the spring is weak it may not be able to throttle the engine against the pull of the govenor arm.