Generator Issues

[cgmartine]

My 4000K (K model) Onan generator has been running great for the last couple of years...until now. I was exercising the generator a couple of weeks ago, and allowed my gas tank to get down to the 1/4 level. My generator shut off like it is supposed to. I have now filled up the gas tank, however, now, the generator is hard to start and will begin to surge, then will shut down with or without a load after about 20 minutes. Is it possible that it sucked some crud from the gas tank and the generator fuel filter is now clogged?

[jerseyjim]

Good advice/thoughts above, but it might be time for a ($$$) pro.

g'luck!

[old_guy]

put some seafoam in it and runit to see if that helps

[hostage]

cgmartine wrote:
Today, Sunday, I went to start it at the storage area. The ambient temperature was 94 in the shade. The generator started immediately. It then ran for twenty minutes (without a load), then began to surge for about 10 seconds, then immediately died. If I read the code correctly, it was 36 (Engine stopped fault). The second time it ran it did the same thing. The gas tank is 3/4 full. The gas gauge is accurate. It is all fresh gas. The third time I had it running and died, I did not get any codes. It is my experience that fuel pumps generally do not run intermittently, so why would it run great for 20 minutes? The same thing with a fuel filter. Once it is clogged, it is clogged. The oil is between the low and full mark. So what is making it surge (remember: no load) and quit running after 20 minutes. Do you all still say it is either the fuel pump or the filter? I will go ahead and replace those, but I suspect they are not the culprits.

will it immediately start and run for another 20 minutes?
if its not producing AC voltage even if theres no draw it will shut down

[cgmartine]

Today, Sunday, I went to start it at the storage area. The ambient temperature was 94 in the shade. The generator started immediately. It then ran for twenty minutes (without a load), then began to surge for about 10 seconds, then immediately died. If I read the code correctly, it was 36 (Engine stopped fault). The second time it ran it did the same thing. The gas tank is 3/4 full. The gas gauge is accurate. It is all fresh gas. The third time I had it running and died, I did not get any codes. It is my experience that fuel pumps generally do not run intermittently, so why would it run great for 20 minutes? The same thing with a fuel filter. Once it is clogged, it is clogged. The oil is between the low and full mark. So what is making it surge (remember: no load) and quit running after 20 minutes. Do you all still say it is either the fuel pump or the filter? I will go ahead and replace those, but I suspect they are not the culprits.

[wa8yxm]

While it is always possible it sucked crud.. ODDS Are very very low as the pick up for the generator is a long way from bottom of tank.

But the advice to change fuel (And air) filters is always good. Also check the oil. Those are 1,2 and 3 and not necessarily in the order listed.

[Peg_Leg]

How long did it sit before you filled the tank? Fuel now days will clog passages in small engine carbs in short order.

[wildmanbaker]

hostage wrote:

K Charles wrote:
Hold the prime just a little longer, if it quits prime it again.

it starts and runs for 20 minutes so no it don't need any priming

OK, if you think it is not a fuel problem, then start over, and check if you have spark after it quits. It could be a heat failure in the spark system. If you have spark, is the pump still supplying fuel? In the 20 minute run, does it load up electrically? After these tests, get back here for more help/information.

[hohenwald48]

Roadpilot wrote:
On my generator there is a bleeder valve. If it runs dry you have to get fuel back in the line.

I believe the 4K generator is a gas generator not a diesel like you probably have.

[hostage]

K Charles wrote:
Hold the prime just a little longer, if it quits prime it again.

it starts and runs for 20 minutes so no it don't need any priming

[K_Charles]

Hold the prime just a little longer, if it quits prime it again.

[hostage]

Ivylog wrote:
How could it suck some crud sitting still and several inches off the bottom of the tank? Changing the fuel filter is cheap enough but may not help. Are you sure you ran it out of fuel...your fuel pump may be going bad or you may have a air leak that is not as bad when the tank is full, same for the fuel pump. You can buy fuel pumps on Amazon for less than $40. By now you may have figured out that I think it's the fuel pump...a common Onan problem.

would be my answer also

[Roadpilot]

On my generator there is a bleeder valve. If it runs dry you have to get fuel back in the line.

[Ivylog]

How could it suck some crud sitting still and several inches off the bottom of the tank? Changing the fuel filter is cheap enough but may not help. Are you sure you ran it out of fuel...your fuel pump may be going bad or you may have a air leak that is not as bad when the tank is full, same for the fuel pump. You can buy fuel pumps on Amazon for less than $40. By now you may have figured out that I think it's the fuel pump...a common Onan problem.

[jerseyjim]

Possible. Now change the fuel filter and find out if that is clogged.