My 454 ran hot yesterday. 240. I shut it off when I saw the steam out exhaust. THANKS GOD I was pulling into my slip. I could spin the seawater pump pulley with my hand. So I took a pipe and wedged it to pull away and ended up with about 2 inch slack.

I think the shop used the belt from the 350 mag the pump came off and the pulleys are different size. No way that belt stretched that far, specially since it isnt new.

Just another reason why I do all my own work.

You might want to do a compression check on both motors and compare the one that got hot with the one that didn't.

Must be a wrong belt.Merc has a couple of different size belts for seawater pumps. One belt has no cogs (larger belt) while the short one has cogs. Chances are you need the smaller one. I think the number off the top of my head is 57-13457t.

The one on it has NO cogs, thanks marinetrans.

Tinkerer, I WISH I had 2 engines in my 22' Pachanga!