MC One running warmer than usual

[turpehar]

I'll try to be brief.

The boat
1982 Celebrity 898, 188v, serial 6068244
Drive Unit; Mercruiser serial 6089398
Transom Assembly Serial 6154420
This has a Rochester 2GV setup tagged as a 1376-8295
and has been modified with electronic ignition.

Last year I didn't get it in the water at all. Busy summer and a few problems with the boat. Those were solved
except when I put it on the muffs in the driveway it got up over 220 so I shut it down. I winterized it and said I will wait until next spring.

Last Saturday my son and I replaced the impeller. We put it back together but then the shift cable wouldn't operate. We pulled the lower unit again and it was just stuck, so we pulled the upper unit and free'd it back up and put it all back together after checking the bearings and bellows. Everything looked good. U joints were tights, and we greased them.

I then put on the carb and got everything connected. It fired on the third crank and then started and ran on the fourth. It sounds good like always. After about ten minutes I raised the RPMs a few times. The temp then started going up and stopped at about 210-220.

I am going to assume I have a restriction somewhere that last year was there but I didn't get that far to see it.

What I would like to hear from you all is what logical places should I be looking for restrictions in flow or exit flow. There doesn't seem to be a lot of water exiting the prop. After it got to 210 and I shut it down there was a bit of steam coming from the rear at the top of the outbard.

 

[Bt Doctur]

Re: MC One running warmer than usual

Was the old impeller destroyed? do you have the merc manual? did you assemble it correctly?
basically its water in ,water out. need both . From the pump thru the copper tube, thru the water pocket cover then to the motor. May have to remove the drive to isolate it. use a washing machine hose cut in half inserted into the water inlet, with motor off there should be a free flow out the exaust ,hose should not be forced out of the housing.
turn on the water, run the motor, rpm`s are basically unlimited without the drive, so 2000rpm wont damage anything. Temps normal=drive issue. hot temp= engine, circ pump, therm housing, manifold, riser/elbow issues.

 

[81 Checkmate]

Re: MC One running warmer than usual

What did the old impeller look like? If it was in peices you have some peices still in the system restricting flow.

Take drive back off and take inlet hose off the themostat...then back flush with garden hose and see if peices come out the inlet hole on the gimble.

BTW....Nice looking boat for a 1982

 

[turpehar]

Re: MC One running warmer than usual

Was the old impeller destroyed? do you have the merc manual? did you assemble it correctly?
basically its water in ,water out. need both . From the pump thru the copper tube, thru the water pocket cover then to the motor. May have to remove the drive to isolate it. use a washing machine hose cut in half inserted into the water inlet, with motor off there should be a free flow out the exaust ,hose should not be forced out of the housing.
turn on the water, run the motor, rpm`s are basically unlimited without the drive, so 2000rpm wont damage anything. Temps normal=drive issue. hot temp= engine, circ pump, therm housing, manifold, riser/elbow issues.

The impeller was shot. We had no difficulty putting it back together. In fact we took the lower unit off three times trying to get the shift cable broke loose. My son is a boat guy and was custom car shop manager,,, blah blah blah, and the list goes on. Not to mention my lifetime of never paying anyone to do anything I can do myself. Not to say we couldn't make a mistake. I'm certain it went back together as it should. The copper tube was clean and the plastic tube was replaced.

I will look at everyones suggestions. Thanks for the response.