25 hp merc water pump replacement question

[modicon2]

I'm attempting to replace the water pump on my 1989? 25 hp merc. I'm not sure of the year...I can't find the serial number but it has A990202 stamped on the freeze plug. If anyone can identify the year based on cowling shape or color please let me know.

These is what I've done:
1) drained lower unit oil
2) removed zinc plate but did not find any bolts to be removed under it.
3) removed the 4 1/2" bolts holding the lower unit on.
It only drops about an 1/2" and appears that the shifting rod is holding it and needs to be disconnected.

Any help would be greatly appreciated!!!
Thanks!

 

[Laddies]

Re: 25 hp merc water pump replacement question

Look under the port side of the carb there is a screw/clip to remove the rod from the shift lever.

 

[modicon2]

Re: 25 hp merc water pump replacement question

I see the clip and screw.
do yo back the screw all the way out?
It looks like if you back the screw all the way out it will allow the clip to slide off the shift lever but still attached to rod. How does the clip come off the rod?

thanks again for all your help.

 

[mthieme]

Re: 25 hp merc water pump replacement question

1986

 

[modicon2]

Re: 25 hp merc water pump replacement question

Ok, I've got the lower unit off and the impeller out.
But the impeller appears to be in good shape (all the ears are attached and not cracking or anything). I know the impeller has not been replaced in several years.

The motor was not peeing with muffs on so I assumed the water pump was bad. Is there something else that could keep it from peeing? or something else that I should check/replace while I've got it broke down?

I can blow air freely from the pee hole into the motor and can blow air on top of the water pump housing down freely.

any ideas?
thanks

 

[cory13]

Re: 25 hp merc water pump replacement question

might be the housing, I've had a crack before that would not allow the pump to pump very well.

 

[modicon2]

Re: 25 hp merc water pump replacement question

Follow up: I got everything back together and it's pumping water!
Important note to remember for the novice like my self is that this motor has a 120degF thermostat. I've only run the motor in the warmer summer months and it started pumping quickly. It was ~30degf outside when I started and got scared when it wasn't "peeing" after running for 10 to 20 seconds...so i assummed it was the water pump.
Hind sight...my impeller did not need replacing (that would explain why it look to be in good shape) but the thermostat just had not opened yet. Anyway I've got a new impellar and fresh lu oil.

Thanks for everyones advice!!!

Notes for others and myself next time I do this job.
1986 Mercury 25 HP pull start.

1) Put motor in forward
2) Remove the 4 bolts hold the lower unit on (no need to remove trim tab)
3) Next you need to disconnect the shift rod where is connects to shift lever up top. There is a black plastic tab with a screw located on the port side of the carb. I took a pair of needle nose visegrips to clamp on the little washer to keep it from falling. I backed the screw all the way out and the plastic clip with pin seperates to allow shift rod fall (helps to have a helping hand) I also removed the side cowling to access the plastic clip but I don't think it was necessary just made it a little easier.
4) Pull the lower unit with shift rod and all out the bottom.
5) Remove 4 bolts connect the impellar housing to the lower unit.
6) Slide housing and impellar up off the drive shaft.
7) Be careful for the washers (1 goes under the impeller and 1 goes on top the impellar)....also keep an eye on the shaft notch/pin thing that locks the impeller to the shaft.
8) Put new impeller on and put housing over it while turning the shaft clockwise.
9) Put everything back together. Be sure that the copper tube shaft for the water pump discharge lines up with tube up in the mid section motor.
10)It only took me ~5 hours but I could do it in half that time now.
Goodluck!

 

[grouper getter]

Re: 25 hp merc mechanical question

Re: 25 hp merc mechanical question

I'm sorrry this is off topic, but you sound like you know your stuff, so I have a question for you; what is this part in the pic called and would it be responsible for not being able to stay in the final gear/ This part broke and the machanic replaced it with a different looking part and now I cant get into final gear and when I do its for about 20 sec.

Please help Mike

mikedarrow16@gmail.com

Follow up: I got everything back together and it's pumping water!
Important note to remember for the novice like my self is that this motor has a 120degF thermostat. I've only run the motor in the warmer summer months and it started pumping quickly. It was ~30degf outside when I started and got scared when it wasn't "peeing" after running for 10 to 20 seconds...so i assummed it was the water pump.
Hind sight...my impeller did not need replacing (that would explain why it look to be in good shape) but the thermostat just had not opened yet. Anyway I've got a new impellar and fresh lu oil.

Thanks for everyones advice!!!

Notes for others and myself next time I do this job.
1986 Mercury 25 HP pull start.

1) Put motor in forward
2) Remove the 4 bolts hold the lower unit on (no need to remove trim tab)
3) Next you need to disconnect the shift rod where is connects to shift lever up top. There is a black plastic tab with a screw located on the port side of the carb. I took a pair of needle nose visegrips to clamp on the little washer to keep it from falling. I backed the screw all the way out and the plastic clip with pin seperates to allow shift rod fall (helps to have a helping hand) I also removed the side cowling to access the plastic clip but I don't think it was necessary just made it a little easier.
4) Pull the lower unit with shift rod and all out the bottom.
5) Remove 4 bolts connect the impellar housing to the lower unit.
6) Slide housing and impellar up off the drive shaft.
7) Be careful for the washers (1 goes under the impeller and 1 goes on top the impellar)....also keep an eye on the shaft notch/pin thing that locks the impeller to the shaft.
8) Put new impeller on and put housing over it while turning the shaft clockwise.
9) Put everything back together. Be sure that the copper tube shaft for the water pump discharge lines up with tube up in the mid section motor.
10)It only took me ~5 hours but I could do it in half that time now.
Goodluck!

 

[modicon2]

Re: 25 hp merc water pump replacement question

Sorry about the delay....I haven't been on the site lately.
I think that part is the "lever-control".

Use the following link to verify.
http://www.crowleymarine.com/mercury_parts/274/40.cfm

 

[joho5]

Re: 25 hp merc water pump replacement question

it should always "pee", that just shows the pump is pumping...when the stat opens, the water comes out of a different hole.

someone correct me if i am wrong here.