How many hours should I change at. Last time they said 20 hours and the oil was like water when it came out. The engines are 496's. How many hours should I put on before changing the oil??

I break in with straight 40 mineral oil and then change
over to 20-50 synthetic amsoil.20 hrs sounds way to long.I
can wear mine out in that amount of time.If your not
broken in after the dyno pulls find a new engine builder.

Well we thought that was too long and changed it after about 12 hours, right after seeing the oil pressure drop to 5lbs. Pulled the motors and had them rebuilt under warranty, now we're going in for the second round. Put about 3 hours on them this weekend so I am gonna change it out now. And yes I do need a new engine builder, problem is I just got into these boats a couple of years ago and didn't know any better, and the engines are under warranty so wehn these one are done, I will definately switch. Thanks for the help.

I just had a rebuilt engine put in my Donzi. I have about five hours on it, and I'm going to change the oil before the next time out. One thing is for sure, you won't hurt them by changing the oil too many times.

Btw, I'm going to synthetic on the next change.

With new flat tappet cams, right after the 30 minute break in. Then 2-5 hrs later, then 20.

With all the moly and other goodies running around in a "fresh" engine, I can't imagine letting it go more than an hr when newly rebuilt.

5 hours first time. Ever 10 hours after first 5.