Generator Clacking

Sprig wrote:

holstein13 wrote:
My Onan 4kw generator has been making a clack, clack, clack noise since I purchased my motorhome...

I have read the entire thread. Does the fuel pump EVER quiet up during the prime process?

I can tell when my Onan 5.5 is fully primed when the clacking stops and the pump silences to a slight buzzing sound.

Knowing that you have the fuel pump replaced, and your descriptions of the systems, I am going to try an online diagnosis:

It is my first opinion that there is a leak somewhere in the fuel line/fittings/etc between the tank and the genset.

This would be like having a small leak in a soda straw. While with a small leak you can actually sip soda, you can never get the full delivery as if there were no leak.

There is a second possibility though. It could be that the float needle in the genset carb is not seating fully. However, you don't indicate that over priming seems to cause a flooded condition. And, it really sounds to me like you believe it to be a fuel starvation issue and not a flooding issue.

Third, and unlikely (but possible) is that for whatever reason everything above is fine, but you still have a bad fuel pump.

This is one of those issues where if many of us were simply there in person it would not take much to determine the root cause. It is frustrating to see people like you take time and money to pay professionals only to continue to have the same problem.

I do understand very well that sometimes the problem is complicated, and multiple steps have to be taken in some instances, but this problem really seems to troubleshoot down to three fairly simple things to check.

Good Luck

Thanks for the comments. Yes, the pump does quiet but not during the priming process. When the system is hot and the generator shuts down, it seams to clack forever. I have not, however, held it down for minutes to find out if it will eventually stop clacking.

I doubt it is a leak because I had Ford drop the tank and do a smoke test. Of course the coach was cool at the time they did the test so a leak is very possible as the coach heats up.

Could it be the float needle in the genset carb? Perhaps, but would the clacking persist even if the generator was priming and the genset turned off?

Unlikely it is a bad fuel pump because the brand new one does exactly the same thing.

Regards,

--Paul