Onan Generator Maintenance

[madhatter1]

While my mains get a lot of love and attention ($$) I was doing an oil change today at 1625 hours. Then thinking about it besides oil the only other thing I serviced in 4 years was the impeller and sea strainer.

What is recommended on a 13.5KW 2003 generator for service? Also what hour interval s is recommended ? We run it a lot. Also I had been using Rotella T-4 oil but they were out so I used T-5 which is a synthetic blend. Is that good or should I go back to T-4 next change?

 

[Captain Ralph]

We have been pouring the T5 Synthetic Blend 15w40 into Cummins, Isuzu, Kubota, Luger, Shibaura and Yanmar diesel gen-sets for years. Always good oil lab reports.
Factory manuals quote 200 or 250 hours for oil service. We have pushed this to 400 on my own personal gen-sets using that blend. Oil lab reports still come back great.
One of our best customers is using full synthetic in his NL 12 & 20 and loves it.

Valve adjustment is usually the first 1000 hours then every 2000 hours.

We always change all fuel filters at time of oil changes.

Order new belt(s) after 1st adjustment is preformed. Always keep a new or used belt as a spare.

Service interval on the impellers. Well, that is a rough topic by itself.
Globe has finally got their last bugs worked out. Instead of the factory NL impellers giving up and requiring replacement with oil changes, A few of our NL customers are getting near 1000 hours now.

Impeller service schedules also depend really on your raw water conditions (silty / clear). Backing into shallow slips don't help either.
Leaning away from the manual on this, Impeller service may just depend on the owners experience when to service.

 

[madhatter1]

This is the first generator that We are putting this much use on. I have been changing oil at the 100 hour mark as that is what the previous owner was doing. Seemed excessive to me as 4 days on the hook meant another oil change. Going to just do it once a year with the mains now. Will get a mechanic in for a valve adjustment. I neglected the impeller and vanes all split and layed over on a day we were anchored out for an event and so I had to go in hot ER and deal with it. After changing impeller and thinking I was home free water was now leaking out the back of the pump. After a while of moving hoses and tightening up the allen bolts on back side we were dry and running. All this time getting intimate with the nice hot genny I notice the whole pump assembly is held on by 2 bolts! I now have a complete new raw water pump in my spare parts storage. It sits with my spare AC pump and AC pump wet section.

 

[Hat52MY]

This is a snap shot from my old Onan MDL4 20KW GenSet maintenance manual. I'm sure it is similar to the Onan 13.5KW. It was a good and dependable unit, but parts kept getting harder to source. We wound up replacing with a new Northern Lights that is very similar in maintenance schedule.