Mercury cooling system question

[thormx11]

I have a 1987 mercury 80hp oil injected engine. Ive had the boat for about a year, and used it about a dozen times or so at the lake. Ive never had any problems with the boat over heating or anything.

Should I be seeing a stream of water shooting out from the upper half of the engine? Ive seen some engines do it before, not sure if my engine is supposed to or not, because it does not shoot any water from the upper half, only from the lower half of the engine.

 

[Chris1956]

Re: Mercury cooling system question

Most Mercs have a telltale to prove the engine is cooling itself. You might look for it and unclog it. It should be on the starboard side of the motor on the lower cowling.

 

[Mi duckdown]

Re: Mercury cooling system question

Ditto. If you don't when the impellar was changed, I would do that also, for peace of mind.
Impellars are cheaper in the long run.

 

[Texasmark]

Re: Mercury cooling system question

If you have a water pump tell tale indicator, ala pee stream indicator, there will be a small hole on the lower right rear (facing forward) of the lower cowling. if you open the cowl and look down in there you will find a hose plumbed back to the block somewhere, cylinder water jacket, top of block, or exhaust water jacket cover. I don't know what you mean about top or bottom.

When the engine is running, at the rear top of the mid section, just below the lower cowling which surrounds the power head....the part I addressed above, are usually 2 holes, could be round or square, which are your exhaust relief....takes the pressure off the engine so that it can breathe when the boat is at rest. Sometimes water/mist/squirts will emanate from there. Perfectly normal.

Some engines, ala some Merc V6's only let pee out when the thermostat opens. You can determine if yours is like that (which is isn't probably) by following the hose to the block and it will go to the thermostat cover...a little cover on the rear of the engine where the water jacket cover is...the one with the spark plugs sticking through it.

Other ideas offered above are there to help you. I just answered your question.

HTH,
Mark