Running Hot

Is your strainer clean? Did you stick in a 140 or 160 degree stat?.

If the water cannot get out of the exhaust, neither can the exhaust gases and the engine thereby would not run at all.

160 - 180 is normal range. Check the thermostat temperature set point.

The thermo is a 140 marine. All strainers are clean. How do I check for rust in the exhaust manifold without a tear down. The boat runs strong other than the overheat.

skyhawkflyer wrote: If you stuck in an automotive type stat those are different, usually 180 degree. Must be marine part.

Completely incorrect. The manifold is jacketed. Water runs inside the jackets and exhaust goes in the center. Only at the end of the elbows do exhaust and water mix. You can have water blocked and still get plenty of exhaust through.

Yes, you are absolutely correct and I agree.

Got a 66 Al tyll skier w/the same problem. Changed the impellers & thermostat, still jumpin up to 220. pulled the thermostat out and still getting all the way up, when I back her down to 1k rpm she cools right down. will update when I pin it down.

My engine was getting up to 200 at speed and would cool back down to 160 at 1k rpm. The trans oil cooler was clogged.

The trans cooler should be above the normal water line while the boat is at rest. Therefore, if you disconnect the water intake hose at the cooler, water should not enter the boat. The water will seek its own level in the hose which would be below the cooler. Just make sure you keep the end of the hose above the water line and not let it fall down into the bilge.

There is not a screen on the inlet, just the grille.

Hope it works out for you. I either overheated it and didnt catch it soon enough or it was already done before I bought it in July but I ended up with blown head gaskets. Finally got it back together and it fired right up for me last night. Going for a test run after work today. It sure felt good to hear the engine start up after having it sit in my garage for a month. Anyways I would hate to see anyone go through what I did for something so simple. Newbie mistake on my part, didnt know to check for something like that.

Thanks '72 mustang, I pulled the hose off the tranny cooler and sure enough found quite a few chunks of impeller. She seems to hold steady at 200 while running flat out, better, but not perfect. Before we couldn't get 2 miles w/o having to back down to idle. Now we can cruise without a problem, I actually got to ski Saturday! Hopefully things still look good when i drop the thermostat back in. The engine's 39 years old so she may have a bit of buildup. Probably save me a bunch of trouble, thanks again, and glad to hear you're back up and running.