I run AMSOIL Series 2000 Race 20W 50W full synthetic. I did the break in change with the recommended Mercruiser oil and then switched to Amsoil after 50 hours. Oil pressure is better than the Mercruiser oil as far as I can tell.

John

Mobil 1 VTwin 20W-50.

Exactly.

Personally, I think merc oil is fine. However, I think most people go too long between changes. Wheather it's synthetic or not, oil still gets dirty fast in boats.

I did about 15 hours on average on my 7.4 between changes. Six years and a total of 850 hours later, and it still ran great! Didn't blow smoke at start-up or anything! Oil changes are cheap! About $36 each time with Merc oil and filter.

Mobil 1 15w-50 is what we put in our 496HO?

I use Mobil 1 V-Twin 20w-50.

Hello everyone and happy Sunday
I am new to this forum but not new to boating
I own a few boats, but my favorite is the 260 Chaparral (496 Mag) . Speaking about that, I am looking to get my oil change done and I ran into a this new oil from Lucas. Has anyone used it? 20w50 Lucas Marine oil? Thoughts ?
Thanks

I think that Merc 4 stroke oil 25-40 is a syn blend and also available as a non synthetic.

My 496HO ran the last 200ish hrs on Mobil Delvac 1300S 15w40 and Mobil1 0w40. 567hrs total. Internals looked great. No need for a 50w oil with stock main/rod bearing clearances IMO.

I ran the Rotella 15-40 for years. I liked that stuff. But, 0-40? Really? I think 0, 5, or even 10 are too light for big block internals.

I prefer 20-50. The15-40 gives me a lower oil pressure when I come back to idle after hard runs. I cant remember what my bearing clearances were but with Amsoil 20-50 I am happy with the performance, plus its red. Red oil is cool.