detergent or non detergent

[BobWaz]

I have a 1987 40 double cabin gas powered. In getting ready for my first winterization wanted to change the oil in my 6.5 Onan. Looked quickly in the book and saw 30 wt was called for. Did not see any mention of oil filter and could not see one on the engine. I brought 30 wt detergent to the counter and asked the guy to check if any of their books mentioned an oil filter. He said not and shouldn't use detergent but non detergent. Without an oil filter the detergent oil will break up the gunk and leave it circulating in the engine without a filter to take it out. At that point it made sense and bought the non detergent oil instead. When back at the boat I checked the book and it called for detergent oil. Went back to the parts place and got the detergent oil. Any thoughts? Is it an oil bath only and no oil pump? No oil filter, why?

 

[captddis]

Use detergent oil.

 

[lake of the woods]

Seems strange that there is not a n oil filter for your generator. E-mail Onan / Cummings (provide them with your generator model number and serial number) and see if they can check the shop manual to see if there should be an oil filter.
I have a gas boat of the same vintage with an Onan 9 kw gas generator. The generator has an oil filter and I change it and the oil at least every 100 hours or season whatever comes first (or if the oil is looking especially dirty). I found that the Onan oil filters for my generator are ridiculously expensive ($35) so I take a filter to my NAPA store and get them to match it up with a Wixs or other similar filter for ($6). Works just fine!

I agree with following the manufacturer’s instructions on oil weight and type is the best course of action.

Mark
Lake of the Woods
1989 40 DC (series 1)

 

[Beachcomber]

My sons boat has the 6.5 gas MCCK Onan and it does not have an oil filter. I just looked in the PDF of the owners manual and it does not list a filter.

 

[BobWaz]

My sons boat has the 6.5 gas MCCK Onan and it does not have an oil filter. I just looked in the PDF of the owners manual and it does not list a filter.

Thank you!