I have a indmar 454 with their log headers. I just bought this boat and keep in mind it’s my first boat I’ve purchased.like an idiot I messed with the valve that controls water flow to my engine not knowing what it was. So I took the boat out for the first time and I opened the valve 2 1/2 turns open. I let the boat idle on the trailer for about 5 minutes and the temp gauge didn’t move at all. I closed it to 2 turns open and took the boat out.just idling around my boat got to about 110. WOT the temp was just registering at 100 which is the lowest my temp gauge goes. After I came back from a run I could hold my hand on the header. It was hot but not unbearable to wear I had to pull my hand off of it. My question is should I keep restricting water flow until my boat actually starts registering about 130-140 at idle?


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On my 454, with logs and snails, I run it at 130 - 140. In no wake zones, it climbs to 155ish.

With open headers, 120 is enough.

Remember, it is a single pass system, lake temp plus 50 degrees is sufficient for open headers.

Logs and snails preheat the water before it goes to the engine. Always keep the temp below 160, where the hard water starts depositing contamination on the inside of the engine.

Just my $0.02

Dan'l

Ok I will adjust accordingly, thanks for the help


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