Overheating Problems

bob faulkner

Recruit
Joined
Aug 4, 2004
Messages
5
Hello to all! I'm brand new to this, so bare with me. I have a 1990 Bayliner with a Force 120 hp powerhead. I had the local dealer replace the water pump and impeller. When I launched the boat the overheat alarm sounded after about 2 minutes. I took the boat back to the dealer and he said that there is not enough water getting to the head? Is there a thermosat that might be the problem? The boat runs well and starts easily, so I do not think the head is cracked? If anyone has any ideas, I could use the help.
 

timfromfc

Petty Officer 2nd Class
Joined
Jul 29, 2004
Messages
149
Re: Overheating Problems

Was the boat idling for the 2 minutes? Mine has done that in the past but when I would rev the engine, more water would circulate and the alarm would turn off.
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: Overheating Problems

You could have a bad thermostat. Most of the time you can descale them and restore their function. Soaking yours for a few hours in vinegar might be worth a try. Otherwise, if the dealer says the powerhead isn't getting enough water to the powerhead, it could be a blockage in the cooling system. Debris can collect in the passage where the powerhead meets the leg. That means pulling the powerhead which sounds major. Well it kinda is, but they come off with suprising ease if you have the right equipment. The hardest part is scraping off the old gasket. You just about need a hammer and chisel. That's something I'd suggest leaving to a dealer. The thermostat thing you can do yourself. It's under a cover above the top sparkplug hole Pay attention to how things come out of there as there are a few parts including a spring pressing against the cover.<br /><br />Tim asks a good question. There is a poppet valve that allows full water flow at higher speeds. That bypasses the thermostat that does it's main job at lower RPMs. If the problem doesn't go away with increased RPMs, then you have a supply problem. (Tim, your problem could be a sticky thermostat as well.)
 

bob faulkner

Recruit
Joined
Aug 4, 2004
Messages
5
Re: Overheating Problems

Originally posted by bob faulkner:<br /> Hello to all! I'm brand new to this, so bare with me. I have a 1990 Bayliner with a Force 120 hp powerhead. I had the local dealer replace the water pump and impeller. When I launched the boat the overheat alarm sounded after about 2 minutes. I took the boat back to the dealer and he said that there is not enough water getting to the head? Is there a thermosat that might be the problem? The boat runs well and starts easily, so I do not think the head is cracked? If anyone has any ideas, I could use the help.
 

bob faulkner

Recruit
Joined
Aug 4, 2004
Messages
5
Re: Overheating Problems

I appreciate the information. I will take a look at the thermostat and check it's condition. I will definetely let the dealer pull the engine if necessary. I was just scared to run the boat with the alarm sounding!
 
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