thermostat, i hope?

[hotmerc]

88 carver santego, twin 4.3 vortecs. went for a cruise and port temp went to normal at start up and no wake speed to open water. on acceleration temp went to about 180 (170 to 175 is normal), then dropped down to almost 100, then up again to 180, then dropped again. at that time overheat alarm went off and i shut it down. thought i might of picked up a bag or something. let the boat sit for a minute and went again with the same result. this is a new engine last summer with new risers, manifolds and 140 degree thermostat. water pump in outdrive was replaced this spring. dont really see any barnacles on the drive yet, but ther coming! and ideas? thanks

 

[Desertsky]

Re: thermostat, i hope?

Are you using raw water cooling or heat exchangers? If exchangers, it sounds like the level may be low or you have a large air bubble trapped in the system.

 

[Don S]

Re: thermostat, i hope?

Thermostats stick, replace it. The fact that it goes to 100? when it opens means the pump is working and there is again flow.

 

[04fxdwgi]

Re: thermostat, i hope?

Thermostats stick, replace it. The fact that it goes to 100? when it opens means the pump is working and there is again flow.

#1 on replace the stat. It's opening and closing, but not where you want it to.