Merc 5.7L engine temp

[Si Rey]

I have a 89 Mercruiser 5.7L 4 barrell Q-jet carb and normal operationg temp is 145 with a raw cooling system. Red line for this engine is 210. I have three Chevy vehicles with Chevy 5.7L EFI engines, all three engines run at 210 and redline is 260. Why the difference in normal operating temps and redline temps on seemingly the same engine?

 

[Don S]

Re: Merc 5.7L engine temp

In short, it's a boat, not a car.

Anything over 180? is too hot for an enclosed engine compartment like a boat has. You would have serious vapor locking problems if you ran an engine in a boat at 210?.

 

[Scaaty]

Re: Merc 5.7L engine temp

Raw water should be 140