MC-1 165 running hot after replacing impeller and exhaust bellow

[AzFisherman84]

My 1977 165 running hot after changing impeller. Storyline, I recently had to replace the upper unit seal because I founded oil in the u-joint bellow. So I figured I would replaced the bellows and impeller why I had the drive apart. I install everything as describe in the service manual, I the only thing I did differently was install exhaust tube instead to a bellow. Now I'm running hot, so my question is could the exhaust tube be the problem or could it be that impeller is not circulating water correctly?

 

[Oshkosh1]

Re: MC-1 165 running hot after replacing impeller and exhaust bellow

Define "hot"...
I also have an Inline 6(raw water cooled). I'm having an issue with the temp gauge and/or sender. According to the gauge, I'm running around 190, but the highest temp read(according to IR)on the actual brass sending unit, the water distrubution block, and virtually any other point I could test in the cooling loop was around 165.

Did you ensure to install the "key" on the driveshaft/impeller...so it will spin?

 

[AzFisherman84]

Re: MC-1 165 running hot after replacing impeller and exhaust bellow

Yes, I did install the impeller key on the drive shaft.
The temp gauge was between 200 and 240 mark, so probably 210 or so and continued to rise. I recently replaced the gauge, temp sender and the thermostat; with the old impeller I was round 180.

 

[achris]

Re: MC-1 165 running hot after replacing impeller and exhaust bellow

The change from bellows to tube on the exhaust would have no bearing on your issue. I suspect you might have missed the water tube when you were re-assembling, it's easily done...

Chris...........

 

[CaptainMak]

Re: MC-1 165 running hot after replacing impeller and exhaust bellow

I also have a 1977 165HP and just did my impeller. Before the work, it ran about 160-180*F constantly. AFTER, the rebuild, I can't even hit 160* if I tried !! Did you install the impeller correctly, spinning the shaft CLOCKWISE while putting the housing over it ? I think if the blades are bent the wrong way, it won't cool as good and will decrease the life of the impeller.

 

[AzFisherman84]

Re: MC-1 165 running hot after replacing impeller and exhaust bellow

I also have a 1977 165HP and just did my impeller. Before the work, it ran about 160-180*F constantly. AFTER, the rebuild, I can't even hit 160* if I tried !! Did you install the impeller correctly, spinning the shaft CLOCKWISE while putting the housing over it ? I think if the blades are bent the wrong way, it won't cool as good and will decrease the life of the impeller.

I pull the drive apart yesterday morning and repeated all the step over again and figured out what I forgot, and that was to use some grease inside the housing prior to use a soap/water mixture to aid in pushing the housing over the impeller. That seemed to do the trick because I put the drive back together last night and fire it up this morning. Back to normal temp again the engine is cool just fine. Thank you for your input.