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NightCrawler 01-21-2018 10:16 AM

Onan Fuel Leak
1 Attachment(s)
New fuel filter head, base and cartridge. Original fuel pump, 1990 8K genset. Fuel now leaking out at the top of the injector pump, just the center one leaks. Never had this before. Fittings have never been touched, still original paint on the hex heads. You can see the fuel puddling around the fixture. The leak is during shut down time as well as when running. Fuel tanks are usually over half full as now, putting about a 2' head of fuel above this area.
Question - is this just a 'snug them up' and be done or does someone see something deeper going on? Genset has ~3,000 hrs. and runs most excellently.

Attachment 72278

Ski in NC 01-21-2018 10:32 AM

Delivery valve holder orings. Can be replaced in situ. Not hard to do, just be meticulous about keeping dirt and paint chips out of pump and put everything back as it came apart.

Look up Kubota D950 injection pump parts diagram to see what is there.

Snugging things up will do no good.

Alaskan Sea-Duction 01-21-2018 11:37 AM

Same thing happened to me on my Onan 8KW. There are small O-rings that have failed and is common with our gennies. By OEM O-rings, not your hardware store variety.

Remove the fuel lines and then the CAREFULLY remove the delivery valve paying attention to the spring and ball. Replace O-ring, reassemble.

dvarholy 01-21-2018 11:55 AM

I have the same issue on the same 8kW generator. The o-rings are Kubota # 15331-9676. The small gaskets are Kubota # 15331-5124.

Alaskan Sea-Duction 01-21-2018 12:38 PM

Thought I had pics, but no. Sorry.

I buy all my Genny parts from below, but beware it will take ay least 10-days or more to get them. They are Onan parts. Much cheaper than getting parts from Cummins. Sometimes, Jacks will tell you the part is no longer available. Call Cummins to get the most recent part number, then go back to Jacks.

NightCrawler 01-21-2018 01:34 PM

Great info. Umonit tomorrow! Thanks all.

dvarholy 03-04-2018 12:28 PM

The non-marine specific parts need not be bought from Onan/Cummins. Any Kubota dealer or aftermarket source can get the parts.


NightCrawler 03-04-2018 03:58 PM

Thanks all for feedback. Injector pump went back together easily, runs great. No leaks. Got the parts from Carolina Diesel in Wilmington, NC. These guys have been great to work with.

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