Hey guys I have a seemingly simple problem that is until I start researching it and all of a sudden it seems NOT so simple anymore? I have a 22' Donzi with a 502 CI BBC very good AFR heads and full roller and an 8-71 supercharger, the exhaust is through hull above water. The problem I am having is I can never seem to get the boat up to any kind of temperature, if I sit and idle for a little while it will get to where it actually registers on the indicator then as soon as I start moving the temp drops back to the peg on the indicator/gauge. There is no thermostat in the cooling system right now but is this as simple as just putting a thermostat in the cooling system? Ans if so what should be the temp rating of the thermostat? I hope its this simple because others are telling me that I need to restrict water to slow the flow down and that a thermostat will do nothing for building heat in the engine.
Please give me some thoughts on how best to cure this issue!

Thanks much
Karl

Actually pretty simple. Many higher hp builds are set up to use cooler water temps and more emphasis on oil temps and engine water psi.

What is your lake/ocean water temps ?

You prob have s crosdover system, but why don’t you.post s oic if the frt if your motor to see it’s rigging.

Cool water temps like you describe are not really an issue and many blower motors are set up that way.
What you need to make sure of is that oil temps are getting into the 200* range.

Quick visual check. Pop the oil cap after a day on the water and see if there is white milky residue on the oil cap. If there is, you are not building enough heat to get rid of the condensation.

Hey guys the lakes I am running in the spring are generally in the 45 to 50 degree range then in the summer it can warm up to the 65 degree area and in the Fall back to the 45 to 50 range after that the boats out of the water for the year. I never thought about the oil temp as being the important factor here, but it seems I have been misguided, primarily by myself! This Spring after running the boat for an hour or so I will pull the oil fill and see if I am getting any of that white stuff inside the cap and I know my boat doesn't have and oil temp gauge on it that looks like a new addition that is needed. If the engine oil temp is low is that going to then require a thermostat in the system, or are we getting into the restricting the water flow to help build heat in the oil?
Thanks much guys for taking the time to answer my question I am sure you all have boats with multiple engines and way bigger than mine so I do very much appreciate your ideas and assistance!!!
Karl

I would run a stat unless your engine is was built to run cooler temps. I suppose if it was then you wouldn't be asking this question. I'm with SB as well when it comes to oil temps, its good to know that the oil is warming up and that its cooling down when it gets too high. To my knowledge most engines are designed to run at certain temps, not as cool as possible. What does your temp gauge read after running it for awhile at higher RPMS

When I launch the boat and fire the engine if I am at the dock with the engine idling I will age at temp reading although it just off the peg at maybe 100 degrees then a take off and within maybe 30 seconds its back to sitting on the peg reading essentially 0 degrees, and that in the summer when its in the Fall and the water temps are down a bit I never get any reading on the gauge. I completely agree with you on the Stat what degree stat would you recommend?
Thanks for your reply also its appreciated!!!
Karl

Is it EFI or carb?
Get an IR temp gun from the local hardware and verify your gauge accuracy.

Its got a 1050 Quick fuel carb and would I shoot the IR temp gun to get a good reading on the engine?

I check different locations if looking for problem. You probably want to shoot close to temp sender to verify gauge.