2001 Mercury 150 overheat.

[Jon1229]

Hi,

i sucked up quite a bit of sand a couple of days ago and my engine started overheating within a few minutes. Since, I have changed my thermostats and water pump, and flushed my engine. At first water could not exit the telltale but I stuck a piece of wire in there to clear it. Now it pisses, has a new water pump and thermostats, but still overheats. It only overheats at high speed also. Tomorrow I will check the poppit valve, but does anyone have any other ideas or suggestions?

 

[Chris1956]

If it isn't the poppit valve, you will have to suspect the cooling passages. Can you reverse flush that motor, maybe thru a flush port, or one of the cooling hoses. If so, you will probably want to drop the gearcase, and put a strainer under the water tube to see if you are getting sand.

 

[Jon1229]

I attached a hose to the port in the picture. The gray nozzle in the back of the motor. I had the lower unit dropped when I did it and sand did come out. Is there a better way to flush the motor?

 

[Jon1229]

 

[Jon1229]

The poppet valve was filled completely with sand. Overheating problem fixed. New question. More water is coming out of the exhaust now then the telltale. Why?

 

[Chris1956]

A lot of those V6 motors have the telltale downstream of the thermostats. You will not have a telltale until (if) the 'stats open. On a cold water flusher device, at idle, the 'stats may not open or open much.

There should always be water exiting the prop and above the A-V plate.

 

[Texasmark]

A lot of those V6 motors have the telltale downstream of the thermostats. You will not have a telltale until (if) the 'stats open. On a cold water flusher device, at idle, the 'stats may not open or open much.

There should always be water exiting the prop and above the A-V plate.

.......aka dribbling out the rear of of the propeller barrel if the engine isn't tilted up.

 

[Rsylvestri]

Telltale comes from the compressor cooling circuit if it's an Optimax, mines starts coming out after 15-20 seconds YMMV