Overheating problem

[lakeboater]

We were out on the lake on the 4th and the boat was running great we had 4 adults and 4 kids (bayliner 1950 3.0 mercruiser) Towards the end of the day i noticed the temp was at around 175-180 never been that high . It has run in a range from 120-140 never higher. So the boat begin to bog down at 3500rpms so i let off it shut it down let the kids swim . After about 1/2 she started right up and we cruised around great then the temp shot up again . So again I killed her up this time she would not turm over wanted to but couldnt. So we got towed in brought the boat back home she sat for around 1- 1 1/2. I put the muffs on and started right up. What could be causing the problem ? Maybe to much load on it working to hard ? Cooling problem ? It is fresh water cooled . allday up intil that last hour she was running at a good temp . Could the thermostat cause this problem ? Thanks for the help

 

[flashback]

Re: Overheating problem

Jay, didn't know they made bayliners in 1950. in any case, my money is on the raw water pump impeller..........let us know....

 

[lakeboater]

Re: Overheating problem

sorry the boat is a 1994 the model is a 1950 lol .

 

[lakeboater]

Re: Overheating problem

Is the raw water pump impeller hard to do -it or self ? Do you also it the theromstat has anything to so with it? Thanks Jay

 

[Blk-n-Blu]

Re: Overheating problem

Jay, Sounds like a fully loaded boat to me. it's always a good idea to let the temperature come back down after running hard by letting the motor run at about 1200 RPM in neutral until the gauge drops to normal temp range. Just my $0.02

 

[lakeboater]

Re: Overheating problem

blk-n-blu Would overloading cause it to overheat like that ? Would it also have trouble starting again ? The 2nd time i let it sit for about 1/2 or so . I shut it down temp didnt really drop to much . But like i said I got it back home and it fired right up . I was just out there throw the muffs on and she fired right up. So I am hoping that all it is , just a overloaded boat. Thanks for the help. Jay

 

[Mikevn1500]

Re: Overheating problem

I had the same problem on July 3. Your post reads just like the one I was ready to type, except one thing. Me and my 8yr old son were the only ones in the boat. We made a 15 mile run at just over 3/4 throttle, shut down to fish then a barge appeared went to start up again cranked very hard and would not start. I used the trolling moter to get clear of river traffic. Temp was at 170 2hrs the thing started again and didn't do it again all day. What I did was to run it for a few minutes before shutting down. My question was going to be is 170 very hot? Car wise this is cold. My boat stays around 160 normally, and I dont have any problems. I cant believe I have only a 10 degree differance between running good or not running at all.

 

[Blk-n-Blu]

Re: Overheating problem

Jay, Running fully loaded for an extended time would probably cause the running hot scenerio you describe.Shutting down a hot motor could cause a re-start problem.IMHO you should always cool down a motor before shutting down as I mentioned above.Even when your alone. After turning the key off the temp gauge usually will stay where it was until the key is turned back on.<br />Mike, 170 doesn't seem excessive after that run but the cool down period should be observed all the time.

 

[Mikevn1500]

Re: Overheating problem

Jay,just to update you on my problem Thermostat was bad. Boat is now running at 140deg. This is alot cooler than my boat has ever run. It must have been on its way out when I bought the boat. Good luck on your problem.