470 Got Hot???

[a1nowell]

I took my '84, JC Tritoon out to fish this morning. About 5 minutes from the marina running about 2200 RPM I noticed the heat guage climbing, the engine got to 200 + degrees before I could shut her down. Water boiled over from the engine into the plastic tank. I went ahead and fished a couple of hours, caught 2 nice channel cats, and it cooled down to where you could touch the engine. I started the engine to go back to the marina and the guage went to about 160 running about 2200 RPM, and stayed. I made a couple of wide loops before going into the marina, temperature stayed at 160. When I got to idle speed and entered the marina the temperature started to rise to about 180. I got the boat on the trailer and ran the engine on the trailer out of gear at about 1200 RPM and the engine started to over heat, close to 200 before I shut it down.

New water pump in the sterndrive in '08. Where do I start to look? Thermostat, engine water pump, heat exchanger ???



Any suggestions?

 

[bruceb58]

Re: 470 Got Hot???

Measure your compression while you are at it because 470s don't like to be overheated. If it only got to 200 you are probably ok though.

Replace the impellor. You need to replace every two years anyway. Then you can see if you need to do more testing.

 

[stonyloam]

Re: 470 Got Hot???

I would be suspicious of the thermostat. Yeah, impeller and compression test are needed. Good luck

 

[a1nowell]

Re: 470 Got Hot???

Stonyloam,
My thoughts are also the thermostat, but for the work to get to it should I also replace the water pump? Also, I remember on old cars just taking out the thermostat and not replacing it , what is my problem if I did that on mine. I'm in the Houston, Texas area, not a lot of problem warming engines up. Lake water temperature is 82 to 90 in the summer.

 

[bruceb58]

Re: 470 Got Hot???

Its worthwhile checking it. I definitely would leave it in though.

 

[stonyloam]

Re: 470 Got Hot???

You still need the thermostat to keep the engine in the proper operating temperature range. If it is working properly even in warmer water you should be OK. Your t-stat should open at 155-162, and be fully open at 182. The fact that worked OK at 2200 and and started to climb at idle, is an indication that it is not getting a enough raw water when the impeller speed is decreased. I would change the impeller first. good luck

 

[Autotech1]

Re: 470 Got Hot???

I got the boat on the trailer and ran the engine on the trailer out of gear at about 1200 RPM and the engine started to over heat, close to 200 before I shut it down.QUOTE]

You did have the outdrive still in the water though right?

 

[a1nowell]

Re: 470 Got Hot???

Yes, when I got the boat on the trailer I and ran the engine it up to 1200 RPM, the boat and trailer were in the lake.