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[SVTotem]

Can anyone recommend a forum for advice on an Onan QD7.5 issue?

My QD 7.5 will run ten minutes and quit. Load is moderate at about 17-20a. Error code is 36 and general service code as best I can tell. Batteries are good, air cleaners is unobstructed. Those are the troubleshooting items shown in the book.

Any suggestions from our group are welcome too, of course.

[94-Newmar]

A friend of ours had the exact same issue occasionally with their QD 7.5. Unfortunately FC36 includes a variety of potential issues. Turned out to be a bad ground to the 12v system used to start the generator. They removed both the pos and neg cables, cleaned them well and haven't had a problem since.

[SVTotem]

Thanks.
Interesting. Any idea why the ground in the start circuit would be an issue if the started and ran for ten minutes? After shut down it would not run if a start was attempted immediately. If started two days later it would run for the same ten minutes and quit with same fault code.

[94-Newmar]

I know I said the same thing - sounds stupid but that is what the problem was. I said well why in the world would you shut it down with a fault code simply because it's starting circuit was questionable. Go figure. I'm glad my older coach doesnt have many of these new fangled monitoring/computerized junk devices on it - I like the "keep it simple stupid" type of equipment

[SVTotem]

I know the EPA has us well past it, but I enjoyed the simplicity of mechanical injection on my sailboat. I will check the ground wire.

[Florida Panhandler]

Bill,
A possibility is your fuel filter is clogged. When was the last time you either changed your generator fuel filter - or possibly treated your tank with biocide. Fuel weeps thru the filter to fill the generator line which lets you run for about 10 minutes. Once you have exhausted that fuel, the clogged filter won't permit sufficient fuel to flow thru to keep the generator running thus starving it. Good luck.

[SVTotem]

Dick,
That is a likely cause. I am the second owner and a review of the records I was given indicates that while the previous owner was diligent in oil and filter changes, there is no indication that the fuel filter was ever changed. I intend to schedule a 1000 hour service (current time is 1921) which will include the filter change among other items. In the process they will likely find any other issue.

In the event that I decide to change the filter myself in the future, how much fuel is lost when disconnecting the lines to the filter?

[SVTotem]

The fault 36 code in this case turned out to be the fuel pump. Replacing it and performing the 1000 service required dropping the genset so it is going to be expensive. Added peace of mind will ease the pain.