Onan Geneator

[goufgators]

My Onan 5500 generator - gas has been cutting off after running 15 to 20 minutes. It always starts right back up but then (again) stopping after running a few minutes. I don't have a clue regarding where to start looking for the problem or if I need to just take to a repair shop. Any ideas, thoughts, suggestions?? Thanks! / Larry

[CarlGeo]

Jim@HiTek wrote:
Here's the best troubleshooting guides I've found:Flight Systems

Agree with Jim, contact Flightsystems and talk with one of their techs. They are very good and diagnosed my problem!
Give them a call.

[goufgators]

Update from OP: Think I've located the problem. There is a fuel leak. Gas is dripping down from an area that I can't see without removing the the air filter bracket. Can't work on it right now but, at least, I believe that to be the culprit! Thanks to all for your comments/suggestions. Larry

[sdbounderdiesel]

x2 on fuel filter being the likely culprit.

[tropical36]

mfox20 wrote:

Gjac wrote:

mfox20 wrote:
Could be a cracked fuel line coming from the tank causing it to suck air. Had the same issue on my 5500 and chased what I thought was overheating, vapor lock issue with no success. Replaced the fuel line all the way from the tank to the generator fuel pump and have not had any more issues.

Quick check....run a line from your genny fuel pump into a gas can on the on ground outside the compartment and see if it keeps running longer than does now. Mine would run in 100 degree weather for a couple of hours from the can and quit after about 20 minutes when hooking the main line back up. Worth a look...cheap fix.

How did you replace the line? Were you able to pull the cracked one out and insert a new one the same length? or did up have to drop the tank?

On my 2000 HR Endeavor I had an access panel in the side of one compartment that when removed allowed access to the area above the fuel tank. This area was part of the overall compartment structure and was made of the same material as my storage bins. In this compartment I found a 12 x 12 hole that had been cut right above the main fuel pump. Through this hole I was able to access the fuel line connection for the generator on top of the fuel tank. Was a tight fit to get in and out but I was successful in replacing the complete line all the way back to the generator. If you don't have anything like this you will need to drop the tank. That will require draining or removing it prior to refilling. Not a hard task with a couple of floor jacks and a couple of small pieces of plywood on top of the jacks, if the tank is near empty. The new gas line solved my generator stopping issues I was having with my Onan 5500. Hope this helps.

Or, with a little studying an ingenuity, one might be able to cut an access hole above the tank and depending on what might be on the floor above. In my case it's the fresh water tank, which is under the bed and should be and easier task, rather than dropping the fuel tank. If I was to be doing the work, I'd rather go this route, if possible.

[mfox20]

Gjac wrote:

mfox20 wrote:
Could be a cracked fuel line coming from the tank causing it to suck air. Had the same issue on my 5500 and chased what I thought was overheating, vapor lock issue with no success. Replaced the fuel line all the way from the tank to the generator fuel pump and have not had any more issues.

Quick check....run a line from your genny fuel pump into a gas can on the on ground outside the compartment and see if it keeps running longer than does now. Mine would run in 100 degree weather for a couple of hours from the can and quit after about 20 minutes when hooking the main line back up. Worth a look...cheap fix.

How did you replace the line? Were you able to pull the cracked one out and insert a new one the same length? or did up have to drop the tank?

On my 2000 HR Endeavor I had an access panel in the side of one compartment that when removed allowed access to the area above the fuel tank. This area was part of the overall compartment structure and was made of the same material as my storage bins. In this compartment I found a 12 x 12 hole that had been cut right above the main fuel pump. Through this hole I was able to access the fuel line connection for the generator on top of the fuel tank. Was a tight fit to get in and out but I was successful in replacing the complete line all the way back to the generator. If you don't have anything like this you will need to drop the tank. That will require draining or removing it prior to refilling. Not a hard task with a couple of floor jacks and a couple of small pieces of plywood on top of the jacks, if the tank is near empty. The new gas line solved my generator stopping issues I was having with my Onan 5500. Hope this helps.

[wa8yxm]

Might be borderline on oil but when I hear "Starts, runs, stopps, restarts, runs stopps" My suspect #1 is the fuel filter. #2 is the air filter, but I've only had one air filter that caused issues,, So #1 is still the fuel filter.

[4ever16]

Mine did the same thing...replaced fuel pump problem went away. be sure to purchase a GOOD quality pump..

[Gjac]

mfox20 wrote:
Could be a cracked fuel line coming from the tank causing it to suck air. Had the same issue on my 5500 and chased what I thought was overheating, vapor lock issue with no success. Replaced the fuel line all the way from the tank to the generator fuel pump and have not had any more issues.

Quick check....run a line from your genny fuel pump into a gas can on the on ground outside the compartment and see if it keeps running longer than does now. Mine would run in 100 degree weather for a couple of hours from the can and quit after about 20 minutes when hooking the main line back up. Worth a look...cheap fix.

How did you replace the line? Were you able to pull the cracked one out and insert a new one the same length? or did up have to drop the tank?

[mfox20]

Could be a cracked fuel line coming from the tank causing it to suck air. Had the same issue on my 5500 and chased what I thought was overheating, vapor lock issue with no success. Replaced the fuel line all the way from the tank to the generator fuel pump and have not had any more issues.

Quick check....run a line from your genny fuel pump into a gas can on the on ground outside the compartment and see if it keeps running longer than does now. Mine would run in 100 degree weather for a couple of hours from the can and quit after about 20 minutes when hooking the main line back up. Worth a look...cheap fix.

[Jim]

Here's the best troubleshooting guides I've found:Flight Systems

[Jef9909]

This unit has a carb- easily gummed up- happened to me last spring. Had carb cleaned, cheaper than new one. There was another piece not working either, it was 19$, and Onan service centre put new plugs in as well. I was getting error code 33, codes are at the back of the manual.

[harley-dave]

On ours it was the fuel pump.

Dave

[ksg5000]

Loose electric connection, low oil, pin hole leak in fuel line, maybe fuel filter. You might try jumping the oil sending sensor - should rule that out.

[Clay_L]

Have you checked the generator start switch for error codes? A code can help sometimes.