Engine oil change

[Mike Harry]

I asked this in another topic and got no answers. Thought I would start a new topic and see if I get any replies.

You cant count on miles in a boat to figure out how often you should change your engine oil, so what do you count on? Hours? If so how many?

I have owned several boats, but this is my first inboard and I am not sure how often it should be changed. I just broke in the fresh motor and have changed it twice since the original firing, but now have the oil in it I plan on running.

Edit: By the way I am running Royal Purple synthetic 10w30

[phil]

What kind of motor? Yes, it's based on the hobbs meter. Now, I'm a anal but in our American Skier with the 351w and flat tappet cam I change the oil every 25hrs(usually 50hr is recommended) and always use Valvoline VR1 Racing oil. It is especially formulated with a high amount of zddp for the high pressure of the flat tappet cams. Most oils don't use these high concentrations anymore because they are harmful to the catalytic converter. I'm sure you will get different answers from different people on this one.  In all my other motors I run Amsoil.

[Mike Harry]

50 hours should be good then? I've run royal purple in everything ever since I used it when I raced cars.  Never use anything else. Valvoline is what I used to break her in.

Anyone else have any suggestions?

Indmar 350 is what I have in the skier (GM based block)

[Midskier]

regardless of what the book says most people just have me change the oil when I winterize their boat........... 50 hours or seasonal which ever comes first is a good guideline
I like dyno oil in fresh rebuilds and new engines, and synthetic in the loose old girls so if they do blow a little by I can't smell it............

Dan T

[Joel]

OOOoooooooo...  Loose Old Girls... now if I could just get some in my boat