Impeller stuck on drive rod, got hot and melted the impeller a little.

I ran my 1986 90 hp Merc inline 6 the other day after rebuilding the carbs. I did not notice that when I let the motor down that the front of the lower unit split the back of the 100 gal tank that I use to run my motors in. When I saw no water coming from the pee tube I shut it down but not quick enough. I have dropped the lower and popped off the plastic housing on the pump. The impeller has kinda welded itself to the drive shaft and I can't get it to move, even with a rubber mallet and a pry bar. Should I cut as much of the rubber off the impeller and put some heat to it??? Would that effect the temper on the shaft??? Anyone else have this problem along the way and know a way to get it loose without damaging the shaft??? thanks for your consideration----

It seems to me that I needed to split a waterpump with a cold chistle, one time. The insert is either brass or fiber, so it was not too tough.

Chris1956 said:

It seems to me that I needed to split a waterpump with a cold chistle, one time. The insert is either brass or fiber, so it was not too tough.

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Thanks for your reply. Funny, I did not even consider splitting the brass sleeve with a chisel. I will go out and give it a shot. Thanks

Actually, after thinking about it some, I needed to split the brass hub on an alum prop that was seized to the propshaft splines. To do that I had to cut off the prop blades and the rubber hub. Then I split the brass hub with a cold chistle.

I never had an impeller seize on me, but I think the approach is sound. I would split the hub where it is thinnest, at the key.

I wonder if the impeller has sorta seized in the pump housing and then spun on the shaft jamming up on the key ....maybe....just a thought

SWAG.....running without cooling/lubricating water on the impeller blades jammed against the walls of the water pump, my guess is that you ran the engine long enough to melt the plastic (not brass) ring on the impeller to the crank shaft. A brass to steel interface would tolerate a lot of heat whereas a plastic ring wouldn't. I think Chris' idea has merit in that a plastic ring would be very easily split with a sharp, narrow,t chisel.

Merc water pump bases melt from the heat of the impeller rubbing against the wearplate. It is from lack of water. The upper pump cover seems to be more resistant to the heat for some reason.

I do not know what the newer resin hubs on the Merc impellers will do under those circumstances. If you have the resin hub, I would be interested in a picture.