1st time out overheating

just checked my impeller 2 weeks ago, looked good with no broken or damaged teeth so I never even removed it from the casing, Marked it with arrows to put it back correctly, however, i thought i tightened the belt enough. When I started the boat on the water it was squeaking from the impeller which led me to shut the boat down and feel the tension. Compared to the belt that is next to and above it, it seemed similar. I had the boat running for no more than 5 minutes at about 8 mph. I let the wife drive at roughly the same speed and she pointed out the red light that indicates over heating or low oil pressure. I shut the boat off check the oil -good, check the tranny fluid -good. then start it drive a bit to see the red light come back on and the temp gauge read about 200. The temp began to climb a bit and I shut it off again to let it cool. We were about 1.5 miles from the ramp so I began to make my way back slowly and the temp did rise to 220.
   A good friend who is a diesel mechanic said a squeaky belt is a loose belt and i am guessing it was not driving the impeller hard enough to get the engine cooled properly. Thoughts,.... and could I have damaged the motor from running it the short amount of time that hot?

Even though 220 isn't too terribly hot, it's much warmer than it should run. For that reason, I would tend to change the oil to be safe. Oil can curdle and lose it's lubricity when overheated. Not being able to see and hear it, it's hard for us to take a guess at it, but it is possible that your squeaking and overheating issues are unrelated.(Worn out water pump impeller or thermostat coupled with bad bearing). First, try and torque the belt a little more (Or buy a new one). If the water pump pulley was spinning, it should be pumping water, but it's possible you weren't gripping enough. You should be able to tell by just watching the pulley spin in comparison with the belt. If there are no outward issues, like I said, you may be dealing with a separate set of problems. Did the boat sit for a long period of time before you ran it last?
Good luck! I'm sure others will chime in.
Jake

Auto engines have pressurized cooling systems and the temp that water BOILS at is higher in pressurized systems.
220*f is high in a non pressurized cooling system

1) take the belt off the R/W pump and turn it by hand

2) black rubber "dust" if the pullies are mis aligned

3) if the belt ajustment is loose try a 1 inch shorter belt

4) if you stop the engine when its hot the temp will continue to climb.

8122pbrainard wrote: Waterdog wrote:    Auto engines have pressurized cooling systems and the temp that water BOILS at is higher in pressurized systems. 220*f is high in a non pressurized cooling system. Pressurized or not, 220 is still the same temperature!

Morning Pete,

   At 220*f in a pressurized cooling system you have water in a
non- pressurized system you have steam and water cools much better
than steam.

Without the science that proves my point.
An engine without a pressurized cooling system is damaged at lower temps that a pressurized one

Two things kill engines.

1) heat

2) friction

Two things kill beer

1) heat

2) light

Oh yeah can i work on the RWP and hoses with the boat in the water? I am in a situation with a fake lake that I need to just back the trailer in to the water and mess with it there.......

Good one Paul I prefer one with more zddp I made this one up,on my boat it is real easy to get to the intake hose at the thru hull so I just remove it there and connect my bucket.Also makes it easy to add antifreeze when it's time too.

When I got in to it today I realized the GT 40 is equipped with a T and short hose at the intake by the strainer.
I pulled the RWP apart to find a melted impeller. Put the new one in and hooked up a hose to my after market rig, verified it was filling the engine and put the RWP back together. Fired it up and the previous noise that I thought was the belt was gone (actually was the shredded impeller). The lesson is NEVER do a dry start in the spring following a drained motor from winterization.      

Thank you all for the always helpful info!