2.3 overheat

[billy boater]

I have a ford 2.3 in my boat and i cant figure out for the life of me whats going on. if im running at 1/4 throttle or more the temp gauge is at 120 but if it is just sitting at idle the temp will slowly climb up all the way past 220 if u let it. if i get the rpm up to say 2000 or so u can watch the gauge go back down (pretty fast) so when its at idle and its starting to get hot if i grab the water inlet hose coming from the outdrive its hot like a rad hose in a car but if im running at 2k rpm or more its cold like it sould be. it goes thru about 2 impellers a summer they look hot and melted like u are running it out of water. i have done everything i know how to do. i work on cars for a living but when it comes to cooling in a marine motor i guess i just dont understand exactly how it works on this motor at least. i have back flushed it to see if i have any broken rubber parts form old impellers and the water flow seems good. new t stat. when i hook the muffs up to the drive and have the impeller housing off water comes out good. checked oil and its not milky or doesent seem like water is in the oil. compression is good in all holes. i am totally stumpped any ideas would be greatly appriciated. thanks..............

 

[tbear1964]

Re: 2.3 overheat

I'm guessing you have a mid/late 80's Bayliner with a Volvo 2.3 L, closed cooled?

If so, your circulation pump for the block may be bad/slipping. You could also have a bad seal in the raw water intake. You stated it had good flow to the impeller housing?

"when i hook the muffs up to the drive and have the impeller housing off water comes out good."

How is this possible with the cover off? You are only seeing water pressure from the muffs, not the suction of the impeller drawing water in. The only thing that proves is it's not clogged to that point. Check the flanges at the impeller housing (in and out) and heat exchanger. If they are cracked, it could be drawing in air and reducing water flow.

Also check the heat exchanger cap for a good seal. The rubber on the cap can wear out. Bad seal=poor circualtion in a closed cooling system.

Good Luck.

 

[billy boater]

Re: 2.3 overheat

thanks for the reply. its a ford 2.3 in a 89 vip vision. i was messin with it today and it just doesent make any sense to me. so the t stat housing has the inlet for the fresh water coming from the drive,then on top of that there is a hose coming off that going to the intake,then the hose coming from the actual water pump then a hose going to what looks like another t stat housing but it just goes shraight into the block. it just doesent make any sense to me why all those hoses are hooked up to the same area of the motor with the t stat in the middle of all those hoses.

 

[bruceb58]

Re: 2.3 overheat

I don't know what motor you have but typically at the thermostat housing you have these hoses:

1)Hose from the drive that is the inlet for the raw water.
2)Large hose that goes to the circulating water pump. This just circulates water through the block.
3)one or more hoses going to your exhaust manifold(usually only one for an inline engine)

Put a clear section of hose between the hose coming from the drive and the thermostat housing. You need to see if you have air getting picked up somehow.

What drive do you have?

 

[billy boater]

Re: 2.3 overheat

i have an omc drive.

 

[bruceb58]

Re: 2.3 overheat

What is the condition of the water pump housing? When you replace the impeller do you replace the gaskets?

 

[billy boater]

Re: 2.3 overheat

yes