Overheating at high RPMs

[AJK737]

Well. I fixed the lifter nloise issue, but now another problem. Replaced the thermostat last year (160 degree thermostat on 5.0 GL-D). Boat runs right at 160 degrees at or below 3000 RPMs. Once I get to higher RPMs it starts to rise. Overheats above 4000 RPMs. It's been a couple years since I've replaced the impeller. Can this be the cause? Any other things I should check also?

Thanks for all the input folks. This is great forum!

 

[Don S]

Re: Overheating at high RPMs

The impeller is the FIRST thing you look at in any overheat problem.