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Bondad · 06-08-2014, 12:07 PM

I pulled my RV from storage yesterday to do some repairs and decided it was time to exerciser the generator. It started within a few seconds and ran for about 10 minutes, then surged for about a minute, then stalled. I checked my fuel gauge and have 3/4 of a tank.

Tried to start it again and it would turn over but initially it would not start. I checked the oil and it spilled over so I know it's full. Tried it again and after about five attempts it started again but did the same thing - ran for 10 minutes, surged then stalled. So I tried it again with the same results - started on attempt 6, ran, surged, stalled.

It has a new air filter but NO fuel filter. A tech told me last fall it had no fuel filter. I was planning to replace it, couldn't find it so took it to a local retired tech.

So if it truly does not have a fuel filter (if he was correct) what would cause thing thing to behave this way?

Perplexed, confused and a little frustrated.

Bondad

George Schweikle · 06-08-2014, 03:10 PM

Once you get the genny running, put a load on it - like the roof A/C, etc.

Quote:

Originally Posted by Bondad

I pulled my RV from storage yesterday to do some repairs and decided it was time to exerciser the generator. It started within a few seconds and ran for about 10 minutes, then surged for about a minute, then stalled. I checked my fuel gauge and have 3/4 of a tank.

Tried to start it again and it would turn over but initially it would not start. I checked the oil and it spilled over so I know it's full. Tried it again and after about five attempts it started again but did the same thing - ran for 10 minutes, surged then stalled. So I tried it again with the same results - started on attempt 6, ran, surged, stalled.

It has a new air filter but NO fuel filter. A tech told me last fall it had no fuel filter. I was planning to replace it, couldn't find it so took it to a local retired tech.

So if it truly does not have a fuel filter (if he was correct) what would cause thing thing to behave this way?

Perplexed, confused and a little frustrated.

Bondad

94-Newmar · 06-08-2014, 06:23 PM

Post your model number for me. The Microlites model number will begin with the letters KY. Depending upon your SPEC you may or may not have the ability to retrieve the error codes being set by the genset when it's failing.

1st - If it is a SPEC F or earlier these units were equipped with a low oil sensor and/or oil pressure sensor - which were notorious for failing and causing the running behavior you're experiencing. These were eliminated as of SPEC H.

2nd - if it doesn't have a fuel filter before the fuel pump then it should. If it has been run without one I suspect the carb has ingested some garbage from the fuel tank which will cause the surging. Unfortunately, rebuild kits for these carbs are virtually non-existent and Onan has forced owners to purchase new carbs.

Bondad · 06-08-2014, 10:55 PM

Thanks for the replies. George, I did put a load on it with the same results. I was hoping it would be that simple.

94-Newmar, I have Model 4.0 KY-FA/26100H. I'm hoping the SPEC you talked about is the H, K or Y in that model number and not the F or the A.

I've been doing some research and it's probably one of three things: Bad Fuel pump that locks up when it gets hot ($75-100?), bad carburetor ($200+??) or bad starting battery.

I'm going out tomorrow to get a new battery 'cause even if that's not the issue, it won't hold a charge so I need one anyway. Which ticks me off because it has a date code of 7/12, has water above all six plates (and always has) and has corrosion pads and grease. But only came with a one year warranty...

Anyway, I'll report back if the new battery solves the problem. If not, it's pump or carb time. YIKES!

94-Newmar · 06-09-2014, 03:57 AM

Quote:

Originally Posted by Bondad

94-Newmar, I have Model 4.0 KY-FA/26100H. I'm hoping the SPEC you talked about is the H, K or Y in that model number and not the F or the A.

Yes, H is your SPEC. You do not have a low oil sensor/pressure sensor, you do not have the ability to retrieve trouble codes from the START/STOP switch.

There is a test for the fuel pump that you can perform. Remove the service cover. Remove the fuel line right at the fuel pump. Aim it into a can. Later SPEC models had the ability to run the fuel pump without running the starter itself by pushing and holding STOP. Since yours does not have this feature you'll need to power the fuel pump with a different source. To test the pump - From underneath, unplug the fuel pump harness and power the fuel pump seperately using jumper wires for 60 seconds. Measure the amount of fuel it pumped. Listen for any unusual noises or rattling from the fuel pump. It may rattle loudly as it begins to pump but should quickly quiet down and pump consistently making only a subtle ticking sound. A proper functioning pump and fuel delivery system will have the ability to produce at least 8-10oz of fuel in 60 seconds.

If it is pumping consistently but not producing enough flow then I suggest checking the fuel filter which is mounted on the inlet side of the pump fuel line inside the generator housing. You can only see it with the front service cover off. Left side, mounted in the tray at the back. It's very difficult to gain access to. Once you get it removed you can try blowing through it. It should offer very little air resistance. Most that I run across that have failed are so plugged with debris you cannot even blow through it.

To save time I use a seperate fuel pump and gasoline supply from a can to hook directly to the carb inlet without having to go thru all this trouble.

Keep us posted.

Bondad · 06-09-2014, 11:03 AM

Thanks for the info 94-Newmar. One quick question. You said to " Remove the fuel line right at the fuel pump. Aim it into a can". Should I remove the line from the pump or the carb? It seems it might be difficult to aim the pump itself into a can but maybe that's accurate. I'm not questioning your advice, I just want to make sure I do this correctly.

To gain access to the pump and filter should I remove the other "stuff" that's in the way? It's pretty tight in there and I can't figure out a way to reach that filter. The only other option I see is to drop the gen but I did that once and it was an all-day affair.

Thanks again!

Bondad

94-Newmar · 06-09-2014, 11:16 AM

Yes remove it from the carb.

Sent from my iPhone using iRV2 - RV Forum

Bondad · 06-17-2014, 07:48 PM

It turns out is was the engine battery! It would not hold a charge so as soon as it got low the generator would lose power from the battery and die. THAT was an easy fix and cheaper than a new carb that's for sure.

I plan to replace the fuel filter (now that I know where it is). Not sure how I'm going to get to it but I'll figure it out.

Now, onto fixing a 1997 Brave Onan 5000 that is not working!

Bondad