Onan 4.0 unusual noise
I have an Onan 4.0 with 14 running hours in my TH and it is making what I think is an unusual noise since about hour 2. Shortly after start up it sounds like there is a quick, loud popping sound that...
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I'm assuming from your signature that your generator is fairly new, so this info probably doesn't apply. In the ~2008-2009 ballpark Onan had a batch of bad valve springs for the ky generators, and many of them broke at low run times. Your 14 hours is right at the sweet spot where these springs broke. Both of mine failed. The symptom was that the generator just stopped running. One spring was broken in multiple places and the other in one place, kinda-sorta still functioning. It's pretty easy to pull the valve cover and check the springs, and you could check the valve clearance at the same time.
