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  1. #1

    Default 25 hp water pump replacement

    I am replacing the water pump on a 1988 25 HP Merc and I have the lower unit 2 inches down , but I cannot get it off . The motor is in neutral but something is keeping it from coming all the way down . ???

  2. #2

    Default Re: 25 hp water pump replacement

    The shift shaft may still be connected. That's usually the first thing you disconnect when removing a lower unit. Mercs typically have a splined shift shaft that simply slips off on it's own however, many of the smaller models back then were actually made by Yamaha. Don't force it. Have a look at the shift shaft and see if it moves up and down to shift gears or if it rotates. If it rotates it's splined. If it moves up and down it needs to be disconnected somewhere close to the lower unit. Some of the old Mercs have a lower unit that's slung back more than normal at the bottom. I'm not sure off the top of my head if your's is that old but I think it is. In that case it wouldn't drop straight down necessarily but pull it a slight to the rear as you lower it and you'll notice it seems to hang or bind on the rear stud. It goes on the same way, a bit difficult and may take a few extra attempts.

  3. #3

    Default Re: 25 hp water pump replacement

    Thanks ! I do beleive it moves up and down when shifting. But I tried what you said and it is still hung up . But I am not 100%sure it is the shift shaft that is hanging up . Could something else be binding it , after it drops down about 2 inches ??

  4. #4

    Default Re: 25 hp water pump replacement

    the shift shaft disconnect is under the engine need to undo the screw and it should come down, it is a screw and plastic sleeve that holds it in place, the rod goes up to the shift lever

  5. #5

    Default Re: 25 hp water pump replacement

    I could be wrong but just in case. If you're sure the shift shaft is disconnected there may be a brass coller near the top of the drive shaft on that model that holds a rubber seal or spacer. It could hang up and you need to give it the right kind of wiggle as you pull it out. I've had that happen to me before, quite confusing but I don't remember exactly what model.

  6. #6

    Default Re: 25 hp water pump replacement

    Thanks , snydes65coupe . I found where the shift shaft was connected under the engine. I did no see that mentioned in any of the other videos or in conversation. The lower unit dropped right out and I am able to repair the water pump !

  7. #7

    Default Re: 25 hp water pump replacement

    ya no problem had to change the water pump on my 20hp this year

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