Merc 9.9/15 smoking and hot

[jay15]

Hi there, I have a 2000 merc 9.9 that we changed into a 15 by changing the carb and it has been working great for about 2 years now, however recently i notice it has been smoking more and more and the water out of the tell-tale hole is pretty hot even after start-up and also after a good run, the upper part of the leg has caked on salt and it has an oily residue, we had the merc rep change the impeller and service the engine, but the problem hasn't changed. Any ideas of what may cause this?
Thanks in advance!

 

[sw9mm]

Re: Merc 9.9/15 smoking and hot

my 15 hp merc tell tale is hot too (hotter than my 15 johnson) and the guy i bought it from said it is normal. he said he had it for three years. called mercury and said the water out of the tell tale should be about 130-140 degrees. haven't used a thermometer but the water out of my tell tale seems as hot as my faucet with hot water only and its set at 120 degrees. i changed thermostat and impeller and same thing. i would check for compression if motor was smokin more than usual. i was a heavy equiptment mechanic but these outboards sometimes throw me for a loop. there a whole different animal from cars and contruction machinery. someone with more outboard experience will surely chime in.

 

[jay15]

Re: Merc 9.9/15 smoking and hot

thanks for the reply sw9mm!
low compression would cause a white.grey smoke? and the tell-tale i noticed has actually gotten hotter than when we first got the engine.
Does anyone else have any input on what white smoke and caked on salt means?

 

[sw9mm]

Re: Merc 9.9/15 smoking and hot

i believe water getting into the combustion chamber can cause some smoke too. i blew a head gasket in my car and white smoke was pouring out the tail pipe.