Definitely was a stock oil cooler. I also believe everyone to be correct on the issue of the 11 lb. bypass. I found other issues as well like the wrong flywheel was installed, wrong pushrods (rockers were hitting valve spring retainers), exhaust valves/ports rusty (you know what causes that), as well as a leaking intake.

The biggest problem for me is that I had absolutely nothing to do with putting this together. All work was done for the previous owner by a shop that I will not name but they are in New Jersey and have been in business a while. I had even called them after buying the boat and they confirmed they did the engine work and that all was on the up and up with what the original owner was telling me.

Honestly get a ZZ502 and drop it in with a marine oil pan etc. It will run like a raped ape.

Wannabe

Make sure you have the right exhaust for that cam that comes in the ZZ's, and also replace the afore-mentioned bypass valve.

Sounds like it was a ticking time bomb. You pulled the pin the minute you started it up. That sucks. :mad: Good luck with the new build.

ok, with the cooler issue addressed, I've seen a few engines from merc with the std relief spring in place, so I don't think thats a total killer, the small pan and the combo of the spring and assuming you had no oil temp gauge, thinking oil just got overheated and died, also if the carb ever flooded and fuel got into the oil would kill so quick make your head swim...I know happened to me...I have a 482 short block if that would help, just out of machine shop assembled...good luck Rob

Thank you but I have a new engine that is going in the boat today actually. And NO, not another automotive 502 crate engine. Also changed flywheel and pushrods on the other motor. New exhaust all the way around and large oil cooler. Oil temp gauges too.