25hp Mercury very hot midsection

[Dspur79]

I have an older 1989 Mercury 25hp 2 stroke that I just got back from the shop. New stator new trigger new coils new spark plugs and all new linkages. The problem is my motor pee stream is very good but last time I was out the midsection is getting very very hot. Evaporates any water that hits it after I ran it. And also it was running great just don't wanna run it with it heating up like that

Also there is no thermostat in the motor and I used to get some water out of relief ports but not anymore

 

[racerone]

I would install a new impeller first.------------Any idea why all those ignition parts were installed ??

 

[Dspur79]

I would install a new impeller first.------------Any idea why all those ignition parts were installed ??

Was told the impeller and water pump were ok but I am def gonna replace. And the last person that had the motor didn't install them right so the flywheel chewed up the wires on trigger and stator. I also was told I had wrong plugs in so the shop gave me the right ones but I just don't understand how this just started happening. Is their any tests I can do to rule out some different parts? Baffles me that it gets so hot right on top of the housing by the exhaust I almost wanna say something in the leg is hooked up wrong. I also got a temperate gun I'm gonna see how hot it is getting in various places today

 

[Dspur79]

Pulled lower unit and a nice size kinda flat black piece of metal was in lower unit by the prop

 

[Dspur79]

No Title

 

[Dspur79]

No Title

 

[Dspur79]

New impeller new water pump new exhaust manifold gaskets. power head exhaust manifold or cylinder cover don't get no where near as hot as they did before but right by the idle relief ports it is soooooo hot

 

[Dspur79]

Any takers on my problem

 

[flyingscott]

Normal. Have you ever noticed that some used mercury motors will have white deposits on the midsection that is from water being boiled off and minerals left behind. My Merc 25 steams the water off of the midsection so I have to clean it once a year. And your motor is cooler Only because you have no thermostat in the motor. The exhaust is hottest closest to the powerhead so the midsection runs warm. See if putting the thermostat back in makes a difference.