overheating

Question
I bought a raw water cooled 2008 5.7 merc. and modified it for freshwateer cooling. it is overheating pretty rapidly. I have rerouted the plumbing to make the shortest runs possible. Water seems to be circulating properly. I did put in a 1 1/4' marelon Sea cock that wasn't full flow. Do you think this could be my problem? Not enough sea water volume.

Answer
Hi Guy....Thank you for selecting the undersigned to reply to your question.

I'm confused about your reference to "raw" and "fresh" water cooling. Are you referring to salt vs fresh water? What would be the purpose of rerouting and shortening any plumbing (hose lines), and minimizing the size of the seacock? How can you be certain you're getting proper circulation? Have you tested the water pressure? When something is designed for a purpose, its best not to modify it, otherwise, you'll end up with problems.

I recommend you consult a qualified and reliable marine mechanic to resolve the symptoms. It may save you money in the long run.

Safe Boating
Ron