Mercury 8hp cooling system failure

[westonschultz]

I have a 1994 mercury 8hp outboard that has been sitting for the past 4 years and the tell tale isn't working. I just went through and put a new impeller. Also checked the exit hose hole with no luck. I am thinking maybe its the thermostat but I don't know if it has one or where it might be?

 

[TQA]

It is likely that all that was wrong was that the pee hole was blocked with scale and corrosion by products.

Gentle rodding with some wire usually gets things going again.

Might be wise to check for water flow from the exhaust by tilting the engine slightly with it running.

 

[CalicoJack]

I seem to remember that these engines have a thermost which when the engine is cold closes the system so that no water can pass, until the engine warms up. As it gets warm the thermostat begins to open letting increasing amounts of water out.

 

[VicS]

I have a 1994 mercury 8hp outboard that has been sitting for the past 4 years and the tell tale isn't working. I just went through and put a new impeller. Also checked the exit hose hole with no luck. I am thinking maybe its the thermostat but I don't know if it has one or where it might be?

Check that the telltale is completely clear Not onl y at the exit in the lower cowl but that the hose and the connection to the engine are also clear.

ITYWF that water will not flow from the telltale until the engine has warmed up and the thermostat opens, but check with your owner's manual.

The thermostat is item 42 in the diagram on this page http://www.boats.net/parts/search/M...0P016999/Cylinder Block and Covers/parts.html
It should open at 120F.

Are you sure the water tube correctly located in the water pump housing after you replaced the impeller?