Changing water pump

[ProCraft17]

I have a 1995 Merc Black max 135
Im very mechanically inclined i just have never changed a waterpump. Is changing the water pump an at home project that i can do or should i shell out the few extra $$.

 

[MacDaddy21]

Re: Changing water pump

It is definitely an at home project. unless your mechanic will do it for free. It really isn't hard at all.

 

[ProCraft17]

Re: Changing water pump

ok. what kind of tools will i need befor i have to go buy somwthing i dont have ...

 

[1fast6]

Re: Changing water pump

I just changed mine today. 1st outboard i ever worked on and i would rate this as one of the easiest jobs i have ever done.
tools you will need are basic hand tools. 5/16 to 9/16 sockets and a 5/8 open end wrench.

don't forget to unhook the vacuum hose thing. i don't even no what it is for:redface:
I tilted motor all the way up. made it easy. If you have a trim tab you will need to remove it as there is a hidden bolt under it.

 

[Eyeman]

Re: Changing water pump

Hey folks, I'm a little confused. If I understand correctly, changing an I/O impeller is different from changing an outboard pump. Let's allow an expert to get us details, but if the Black Max is anything like my 1996 Mariner, you have to drop the lower unit to get to the pump. It's simple, but there are a few tricks. The vacuum hose thing is the speedometer tube. Drain fluid, remove lock nuts and washers. You might have to remove the trim tab thingie to get access to a bolt. You'll need to either have the trans in forward or neutral? Again, we'll leave the details to an expert, but there are some various wrench requirements, box ends, 1/4" drive socket(5/16"), 3/8" drive sockets w/extensions (5/8", 7/16"), slotted screw driver, a block of wood (nice to set the lower unit on) and of course the BFH.

 

[robert graham]

Re: Changing water pump

I have a 1995 Merc Black max 135
Im very mechanically inclined i just have never changed a waterpump. Is changing the water pump an at home project that i can do or should i shell out the few extra $$.

Check: SIM Yamaha- Andy's Tips for step by step instructions with photos on water pump impellar replacement, plus several other repair/maintenance procedures. It's a Yamaha, but most of the basics should be the same for Mercury. I did my pump a while back(not that hard to do), and Andy's Tips helped a lot for a general feel for what's required. Good Luck!

 

[Chris1956]

Re: Changing water pump

Eyeman, The waterpump repair on an Alpha I or Mercury OB gearcase is identical. There are some minor differences removing the gearcase from the motors. Alpha gearcases need to be in forward, or you will break the shift linkage. You also need to drain the gear oil and leave the prop on the Alpha gearcase, so the gear oil doesn't leak all over and you can mesh the driveshaft upon reassembly. There is also an oring that seals the upper and lower gearcases

The Merc OB should be in neutral for removal and installation. You an turn the flywheel by hand to mesh the driveshaft with the crank.

In both cases you will need a 5/8" or 9/16" (I forget which) open end wrench and socket. To remove the zinc anode requires an allen wrench or thin wall socket, depending on what holds it on. The hidden bolt is a size smaller and requires a socket to remove it. the waterpump needs standard open end or socket wrenches. There are small differences in bolt size and type.

Make sure you replace the impeller, wearplate and the two gaskets. Inspect the upper pump cover for wear, and if there is any water leakage into the gearcase, replace the pump base, which has the driveshaft seal, as well as the base oring and gasket.

 

[Chris1956]

Re: Changing water pump

One more thing. A BFH should not be used. Wiggle the gearcase into position, using your fingers to tighten the bolts. Grease the splines of driveshaft and shift shaft. I cost the driveshaft with marine grease since I boat in salt water.

 

[ProCraft17]

Re: Changing water pump

Thanks guys.
I changed it today but couldnt test it just yet. I greased all splines and put new seal between exhaust and water pump . My old seal was broken allowing exhaust gasses into the water pump. It went well an everything went in good except the driveshaft but with a little movment of the flywheel it went into place.

 

[KRS62]

Re: Changing water pump

I think there are a few youtube vids that might give you a good head start.

 

[1fast6]

Re: Changing water pump

Thanks guys.
I changed it today but couldnt test it just yet. I greased all splines and put new seal between exhaust and water pump . My old seal was broken allowing exhaust gasses into the water pump. It went well an everything went in good except the driveshaft but with a little movment of the flywheel it went into place.

Glad to see it went well.

 

[Eyeman]

Re: Changing water pump

Eyeman, The waterpump repair on an Alpha I or Mercury OB gearcase is identical. There are some minor differences removing the gearcase from the motors. Alpha gearcases need to be in forward, or you will break the shift linkage. You also need to drain the gear oil and leave the prop on the Alpha gearcase, so the gear oil doesn't leak all over and you can mesh the driveshaft upon reassembly. There is also an oring that seals the upper and lower gearcases

The Merc OB should be in neutral for removal and installation. You an turn the flywheel by hand to mesh the driveshaft with the crank.

In both cases you will need a 5/8" or 9/16" (I forget which) open end wrench and socket. To remove the zinc anode requires an allen wrench or thin wall socket, depending on what holds it on. The hidden bolt is a size smaller and requires a socket to remove it. the waterpump needs standard open end or socket wrenches. There are small differences in bolt size and type.

Make sure you replace the impeller, wearplate and the two gaskets. Inspect the upper pump cover for wear, and if there is any water leakage into the gearcase, replace the pump base, which has the driveshaft seal, as well as the base oring and gasket.

Thanks for the schooling. This all makes really good sense. Regarding the BFH - I used it to tap on the box end wrench rather than busting up my palm.