mercury 65hp need some help

[matt246]

hi there i went out today in my 65hp blueband 2 stroke outboard and it was running fine and was left on full throttle for about less than a minuite and it was pumping water fine but it suddenly started pumping steam instead of water and it overheated as i was eager to get back to the peir before it did, but the outboard cut out and we had to row back as i had forgotten my backup outboard .i had fited a new water pump kit several weeks before and we ran it in a tub in neutral mostly and it didnt overheat is it a head gasket or simply that the impeller is recked and metled or something

 

[Fuzzytbay]

Re: mercury 65hp need some help

Check to make sure the intake didn't get cloged up. Second, revisit the waterpump (pickup tube came out maybe). Third, I hope you didn't damage the engine, check out the compression on the cylinders, and check the plugs, for "metal flakes". Depending upon how long you ran it, it might not have much damage, but I guess since it "siezed" up, you "hurt" something. I am not meaning to throw salt on a wound, but when it first started pumping steam, you should have shut down, and let it cool, then start up and troll back, shuting the engine down as it started to get hot. I mention this so maybe others who read this post, might learn from your mistake. Good luck and let us know the outcome.

 

[matt246]

Re: mercury 65hp need some help

hi there sorry for taking so long to reply.i went to check the outboard today and the sparkplugs on the top two cylinders had metal flakes come off them but the bottom cylinder was ok with a bit of oil on it.after taking off the lower unit i saw that the exhaust had melted the rubber seal that goes round it on the lower unit and there was nothing blocking the water pump intake .i will take apart the water pump tomorrow to find out whats happened but it sounded like everything was alright and the impeller wasnt loose after turning the shaft do you think that there is a blown gasket somewhere i will compression test it tomorrow. thnaks

 

[sschefer]

Re: mercury 65hp need some help

Did you check the water tube connector from the water pump outlet to the water tube.. It was there wasn't it?

 

[matt246]

Re: mercury 65hp need some help

hi there thanks for the reply im not sure what you mean as there is just a copper pipe coming down and it slotts right into the water pump housing and that seems to be fine also the outboard ran without water pumping until it stopped or cut out does this mean iv damaged something like thermostat or gaskets??also what is the purpose of the thermostat if it doesnt shut off the engine if it gets to hot and it doesnt regulate the water flow should it shut something off if it got too hot or be like an alarm??another thing is what does the metal flakes coming off the two top spark plugs mean and not the bottom one does thi mean that the top two got so hot that the metal flaked off them but why not the bottom one??sorry for all the questions thanks for your help tho

 

[sschefer]

Re: mercury 65hp need some help

It these are metal flakes, not melted aluminum, the are probalbly from the cylinder sleeve which indicates ring scoring of the cylinder walls. The lower cylinders might have not been affected because what cooling water was getting through was built up around those cylinders but the pump was not making enough water to fully flood the chamber.

The thermostat does open and close according to temp when it is working properly there will be some water flow during warm up but not enough to keep the engine cool when running at speed.
The thermostat is a temperature sensitive valve and commonly opens at around 140 degrees. It does not have a mechanism for triggering an alarm.

Your engine may or may not have a temp sensor which is in direct contact with the exhaust cover or some other location where an average temperature can be monitored. It can be wired to work with a gauge but most commonly is connected to an alarm box which is nothing more than an audible idiot light.



On some of the newer engines the alarm modules work together with the ignition systems to reduce engine rpm and place the engine into what is known as limp mode so you can limp home without causing more damage.

Also, you water tube is correct without a sleeve like some of the others.