77 25hp evinrude running hot

[tdr9499]

can anyone please tell me why the motor is still running hot! i have replaced the impeller and the thremostat, both. the water coming out of the telltale is cool to the touch but the motor is extremely hot. the motor will steam if you dump a hand full of water on it. it acts like the water is not going though the motor. is there any where i should look for blockage. thanks for any input

 

[WillyBWright]

Re: 77 25hp evinrude running hot

I'd suggest removing the head and see if sand or scale is creating some blockage in the cooling passages. If there is thick scaling, you can eat it off with Acid Wash or Milkstone Remover and not damage the aluminum. Muriatic acid and Zing can damage the aluminum.

 

[rickdb1boat]

Re: 77 25hp evinrude running hot

Remove the lower unit again and remove the T-Stat and flush it out through the water tube. This should clear out any debris in the water passages. Were the impeller vanes facing the correct(Clockwise)when you installed it? Key in impeller to driveshaft? Was the old impeller missing any vanes or torn up?

 

[fishingdeal007]

Re: 77 25hp evinrude running hot

tdr, first check your compression to make sure the cylinders match. If thats ok more than likely you have got corrosion thats built up in your water passages in the cylinder head restricting water flow.

 

[tdr9499]

Re: 77 25hp evinrude running hot

the motor is peeing fine, it is just the water is cool coming out and the motor is running hot. where should i start looking for possible blockage in the motor

 

[P.V.]

Re: 77 25hp evinrude running hot

Well, if you're confident that all other inspections are OK, I'd suspect the water tube and gromett under the powerhead. This is where the upper water tube connects to allow water to enter the bottom of the block. I've seen the block get hot and litterially melt the tube and restrict flow. It will require pwrhd removal and then you'll see the plastic tube! Hope that's it! BTW, If you only replaced the impellor, I'd do the whole water pump kit as an assembly first. I don't like just doing the impellor when your chasing a cooling problem!!