Overheating While Sitting

[tigeky]

2004 24V with the 6.0 375 hp Marine Power

New impeller & new water pump. Enclosed cooling.

Boat runs really cool when running. Intakes are really cool to the touch while sitting but the motor is over heating. I have to put it in gear and limp along until the motor cools back down before I can take off. Last time at the dock the temp just kept creeping up but luckily was able to get under way before it went over 240ish. Not sure how bad that was and have no idea how hot is too hot. Every time I sit the temp creeps up.

Any ideas why the lake water isn't cooling the coolant? FYI, this was a couple of weeks ago when the water temp was 74.

[Wakeman22]

Go searching for the pieces of the old empeler. They will be caught up in the lines and or trans cooler. Search and you will find where others have found pieces.

[freeheel4life]

Possible stuck thermostat...
Possible circulation pump isn't moving the coolant...

Just two more things to think about. You can always pull the thermostat and run it and see if it continues to overheat

[tigeky]

Thanks for the advice Wakeman22, you were right. Now I have a new problem, new meaning I have never experienced and I have experienced a lot of problems when it comes to my engine. So here it is, The boat ran well for 2.5 times after the empeler pieces were removed. The other .5 happened Saturday while my daughter was trying to wake surf. No power. I had been riding for 30 minutes or so without any issues. It had the same feeling as when the boat would temp up over 200 degrees and I had to idle around until the temperature dropped to 190 or so (hopefully the empeler clean out fixed this problem).

The empeler was inspected during the cleanout process and was deemed to be in good shape.

Here is what was going on,

Motor runs fine at idle.
Temp was at 190ish and stayed there. Engine never got hot.
Once I got into the throttle it would have some power than it would start to bog down.
The red light on the dash stayed on while idling. 1st Time for that.
The coolant overflow was full (see pic). First time when the motor temp was fine.

So.... I shut if off, we sat for an hour then limped it back to the ramp. During which the temp stayed constant, power did not return, the coolant overflow stayed full.


Ideas?

Note: The rag on the fuel pump was a result of a suggestion to vapor lock post 8 or so years ago.

[Bamer]

190? Should the thermostat is your boat be a 160deg?


Sent from my iPhone using Tapatalk

[freeheel4life]

If you have cleaned out all the old impeller theres only a few other things in my mind to point to. A blockage on the suction/intake side before the raw water pump. I can't remember if the trans cooler is pre raw water pump on this configuration, but if it is some debris could be slowing raw water flow at higher RPMs inside the cooler. A suction/intake hose sucking air can also lead to low water flow so check hose clamps and hose condition from the thru hill to the water pump.

If you have been running for a while in sand/Beach the boat/ scummy water the heat exchanger could be plugged up. Have seen it happen after a single beaching in sand that got stirred up leaving the beach..

Circ pump not moving coolant, stuck thermostat, or air bubble in the coolant loop would be the only other 3 I can think of.

[boatwakes]

Finally found the thread. Here's the resolution:

https://www.tigeowners.com/forum/tec...-0-cooling-mod

[freeheel4life]

Boatwakes for the win as usual.