As I have been spending so much time around the engine as of late I am going to do the oil next…wondering if anyone has a favorite brand and viscosity of oil in hot climate operating conditions?

I am thinking Mobil 1 synthetic as I have had good luck with it in other applications….

Oil Viscosity should be as recommended in Yanmar Service Manual for outside temperature ranges – SAE 10W-30 will cover you for most of North America for year round use. If the water temperature is above 95 degrees, use 50W oil. The service grade should be SAE CB or CC for moderate duty diesel engine service.

I have the older 2QM15. First time I changed the oil I used 10W 30 and it suddenly became hard to start on cold days. Got a lecture from my mechanical engineer dad about reading manuals and did so. I believe it calls for 5W. I used Mobile 1. Starts much easier. ("Started" I suppose since I haven't turned the key in almost 4 years.)

Unfortunately I have not been able to locate a QM15 manual online….I do know that the GM15 manual suggests 10W-30 I would expect the QM and GM would likely take the same oil.

From most of my diesel experience I have generally found 15W-40 outperforms 10w-30. While on the same theme does anyone know the Fram filter part number ? Once again I am assuming that GM and QM likely take the same filter…

IGNORE the oil filter question....I found the answer in the archives here... it is a Fram PH3593A

Do you mean the 5W-50 Mobil 1 ?

It's been a long time, but I think I have a bottle in my garage. I'll check tonight. My mind recalls it just as 5W, but I think you're partly correct. It may be 5W 20. The 2QM runs cooler than the 2GM. This may be the reason. I believe the 2QM was really ment to be a generator engine.

Here's the marine operators manual for the 2QM15: http://www.g-o.dk/Files/Billeder/PDFer/YANMAR/Instruktionsbger/2QM15.pdf

It says to change with the season, 10W when it's cold and 20W when it's warm, 30 W or 40W when hot, and 50W when REALLY hot.

I really need to look at that bottle.

This from the 2GM Yanmar Operations manual....

Thanks for posting that link – much appreciated. The only other one I found online for the QM was a broken link.

Filter Question.....the site here lists a Fram PH3593A as the Yanmar replacement filter....However Fram no longer lists that filter on the Fram website and instead now shows a Fram PH5046 as being the Yanmar OEM replacement on the QM15.....has anyone tried a Fram PH5046 ???