'95 Minnie Winnie Gen / AC Question

[Bob55]

Our 1995 Minnie Winnie shows only 289 hours on the generator meter, so it hasn't been run much by the previous owner(s). My wife is very heat sensitive so I wanted to be able to run the AC off of the generator (Onan 4000) so she could stock the coach and arrange things prior to our next trip.

I fired the Onan up, let it smooth out after about 10 minutes of running, and turned on the ceiling AC.....the generator immediately started to lug down and cycle so I shut off the AC. Once the generator settled down and ran smooth again I cycled through the AC settings for the fan, and then hit "low cool", again the generator started to cycle and wanted to stop.

Round two, I moved the temp control to mid-dial, and re-did the low-fan, high fan, and low cool switch, and then moved the temp control another notch (is this making sense?).

As soon as I moved the temp control switch to max (at low cool on the other switch) the generator again started to cycle and almost quit/stall.

Is this typical for a generator that hasn't been used much? I can certainly exercise it by slowly adding load to it over several run sessions if that will help. Are there other PM items I can do to help?

We're new to this and certainly appreciate any feedback or pointers!

[Jbmsr]

Originally Posted by Bob55

Our 1995 Minnie Winnie shows only 289 hours on the generator meter, so it hasn't been run much by the previous owner(s). My wife is very heat sensitive so I wanted to be able to run the AC off of the generator (Onan 4000) so she could stock the coach and arrange things prior to our next trip.

I fired the Onan up, let it smooth out after about 10 minutes of running, and turned on the ceiling AC.....the generator immediately started to lug down and cycle so I shut off the AC. Once the generator settled down and ran smooth again I cycled through the AC settings for the fan, and then hit "low cool", again the generator started to cycle and wanted to stop.

Round two, I moved the temp control to mid-dial, and re-did the low-fan, high fan, and low cool switch, and then moved the temp control another notch (is this making sense?).

As soon as I moved the temp control switch to max (at low cool on the other switch) the generator again started to cycle and almost quit/stall.

Is this typical for a generator that hasn't been used much? I can certainly exercise it by slowly adding load to it over several run sessions if that will help. Are there other PM items I can do to help?

We're new to this and certainly appreciate any feedback or pointers!

I believe you have a basement unit with two compressor. On low it calls for one to run then on high it calls for two. Seem the second compressor is more of a load than it wants to handle. That is very low hours. I would turn all other items off like the water heater, microwave, coffee pot. And try again. It really should run both compressors. If the ac works on hi when on shore power then the genset is not up to par. Running and using a generator many times makes for a better running generator. I would service it and if it continues to underperform I would have Cummins look at it.
Jesse

[John Hilley]

You don't have basement AC with two compressors. How does the AC work on shore power?

[Lt46]

The previous owners didn't do you any favors. An RV generator needs to run and run often. In fact, the owners manual will give you a schedule for monthly run-ups. Given what you've told us, I'm wondering, as is J. Hilley above, how does the AC run when plugged in? It sounds like the genset is running OK w/o the AC turned on but bogs down once the compressor fires up. You might have a compressor issue.
I'd do as you suggested, run genset and slowly load it up with anything, but the AC and she how she behaves. I'd also run the AC on shore power and see how it behaves. Once you get it narrowed down, further testing with a volt meter will zero in on the issue. Good luck.

[Bob55]

I spent some time yesterday exercising the generator as suggested, and might have worked the bugs out of things. I started it and let it run for 20 minutes with no load, and then for the next 20 minutes ran it with a light load (fans and lights). I added the AC to the load in fan only mode and let things run for another 20 minutes. I took those loads off, let the genset run non-loaded for 10 minutes, took a deep breath, and turned the AC to low cool and slowly turned the temp setting to coolest. No stumble! I let it run that way for 45 minutes without hesitation. With everything running smooth I took a gamble and switched the AC to high cool with the thermostat at the higher temp, no stumble or trouble at all. I then turned the thermostat to the coolest setting and just let things run for an hour. At that point, I shut the AC off and let the genset run 10 minutes unloaded before shutting it off.

It seems that very slowly adding load might have worked!

[Lt46]

Yup, sounds good to me. Probably needed the exercise.

[okcnewbie]

While the genset is running good you could pick up a Kill-a-Watt Meter ($20) from Harbor Freight or somewhere else. This will allow you to verify that your no load voltage/frequency readings are about 128ish/63ish and your load values are 120/60 ish.
I suspect that the slip rings on your generator could use some cleaning. When dirty the voltage regulator is asked to do more than normal and can die earlier than usual.
It's probably a bit presumptuous of me but I'm assuming you have a onan genset.
Good luck.

[NeilV]

You might want to add so fuel system cleaner to the gas tank the for the next time you run the generator. The carburetor bowl probably evaporated all the gasoline some time ago and had some corrosion in it. They no longer sell the parts to rebuild the carburetors so keeping them clean and running the generator often is important.

[Bob55]

Yup, it's an Onan, model Microlite 4000. Gave it a couple more runs and all seemed to work okay. Are the genset slip rings something an owner can clean if needed?

Good suggestion about the fuel cleaner additive, it would probably help the rest of the system as well!