Motor overheating when trolling

[fishin2]

No,nothing missing. Was just a little dry and I replace it every other year, needed or not. Only had the boat 2yrs and this is the first time pullin boards with it and she got a hot at an idle. Gonna check into an impeller housing today, just might be the way to go, replace everything and eliminate that possibility. Thanks fellas, your always a great help, Mike

[BILLY JOE]

could be the water jackets in your exaust manifold are starting to corrode shut creating a water flow problem this happens alot to salt water engines. just a thought

[sherman51]

do you have the closed water system with the raw water pump on the front of your motor, or do you have the outdrive pump?? if you have the closed water system it could just be alittle low on antifreeze. or you could have a bad impeller.

we was working on my motor one time on my mercruiser and we shut the water off to the outdrive. and did some work. then started the motor back up, then noticed we hadnt turned the water back on. so we shut it off and turned the water back on. well everything seemed to be ok, untill i put it on the water. then she overheated, so i replaced the impeller. took her back out and she idled just fine, it was whan we took off down the lake that it overheated. i tried everything i could think of. i replaced the water line on the outdrive run a wire through the pipe that goes through the transome and replaced the water line from the transome to the motor, she still overheated. then i was told to replace the impeller housing and the bottom wear plate. that fixed my problem.

now i talk to this guy on another forum. he has a boat but i dont know much about it except it has the volvo penta outdrive. but year before last he had put a new inpeller in his water pump. but it started overheating at trolling speed. he even took the manifolds off and cleaned them. he just couldnt get it fixed, he took it to another guy to see if he could fix it. he changed the impeller again and that fixed it. i guess he had either damaged the new impeller or just got a bad one to start with. but it had only lasted about 6 weeks.

if you have the outdrive pump i would suggest you change the impeller and upper housing and the wear plate. if you have the raw water pump on the front of your motor i would try just changing the impeller first. then if that didnt fix it i would change the housing. just my opinion.
sherman

[fishin2]

Ordered a complete rebuild kit for the impellar, complete new housing, wear plate, new gaskets,o-rings, and a new water tube, and new impellar. Might as well start with the easy stuff, again, thanks all, hope she trolls good this year cause the jig bite will get most of my milk money !!! Oh yea, I have an open raw water system, impellar in my outdrive type. Mike