1994 150hp Johnson Water Pump

[rdgallo]

In the near future, I will be replacing the water pump on this engine. I do have an OEM manual for it. Do any of you have any special short cuts/important tips for changing this water pump. The engine has the original pump on it and I am not having any problems with it as far as I know. Just thought after 10 years, I should replace it. I know the manual states to use certain OMC products when replacing the pump (sealant, etc.). Are there any of these things that I could purchase at a local automotive parts store? OR should I be sure to go to the OMC dealer and get what the book calls for? Thanks in advace.

[Walker]

10 years old! Put a full water pump kit in it. Its pretty easy to disconnect the shift lever but I find it much easier to re-connect it by splitting the cowling pan so you can see and get to the linkage easier.

[guyo]

careful when you pull down the lower unit do not disturb the shift lever height otherwise you will have shifting trouble replacing a water pump is not very difficult a service manual would pay for itself 10x over good luck

[marinemech1]

i agree with walker "full kit" as there have been a few upgrades to pump be sure to use oem pump and take model number in to be sure you get the correct kit (there are 2 kits avaiable they look simiar but are differnt)as for the special sealant best to buy what manual states to ensure product will do what its suppose to

[rdgallo]

Thanks, guys, for the responses.

[rdgallo]

I just finished putting the water pump kit in my 150 hp Johnson. The only lproblem I had was getting the shifting shaft hooked back up. Everytime I would slide the lower unit in place the shift shaft would hit something putting it all the way down and actually turning it a little. I eventually got it hooked back up after putting the lower unit in place by using a pair of long needle nosed pliers and lifing on the shift shaft in an area down further on the shaft where it is exposed. What a pain in the butt to hook this back up. There must be an easier way, or Johnson needs to kill an engineer or two.

[angus63]

You'll need adhesive M, gasket sealer, and marine grease. Remove the air silencer and the screw for the shift is under the bottom right carb looking at the motor. Shifted into forward it's alot easier to access. I suggest someone supports the lower unit when you remove the last bolt cuss it will sag a bunch and strain the shaft. Two bolts are near and under the trim tab that are different sizes (total of six, keep track which go where). Pull the unit straight out and have something to support it (I use a 25 gallon can). Follow instructions in the book for disassembly. Clean all mating surfaces well. Do not get adhesive in the bleed hole of the housing (you'll see). A picture of the parts you remove in order will help you remember what goes where. Assembly is relatively staight forward. Be sure vanes on the pump are biased in the same direction of the one you removed when you put it in the housing and the slot for the shaft key is facing away from the housing!!!! Be sure the delrin shaft key is free of burrs before trying to slide impellar on. Do Not turn the shaft counter clockwise after assembly!!Check your shaft length (20" no extension on water tube/// 25" short extension on water tube///// 30" long extension on water tube.). Carefully slide unit back on and guide the shaft, water tube, and shift rod into their appropriate openings. Torque bolts to spec (too tight will strip th'd holes!!) and use some antiseize so NEXT YEAR this will be much easier. Do not let it go past two years for the next change (cheap insurance)! Put the muffs on with full hose pressure and let water circulate a minute or so before cranking. The flow from the pee hole should be strong and steady within 5-10 seconds after starting. If you have any problems along the way, post back and we'll see ya thru.Good luck

[rdgallo]

Thanks very much, Angus. Actually, I put the repair kit in about 1 week ago the first time, but screwed up and put the water pump plate gasket on top of the plate instead of on the bottom. We had trouble hooking the shift rod back up, but finally succeeded. A little later in the day I realized my mistake with the gasket. So, ordered a new one and redid everything today. Again the only problem I had was hooking up the shift rod, but got it. I have one question though. Is there an o'ring that is supposed to be at the top of the driveshaft? I had one in the kit, but the oem service manual doesn't mention or show one at the top of the driveshaft. The paper that came with the water pump kit shows one in one area of the instructions and none in another area of the instructions. I did not install one at the top of the shaft. Do you know whether it should have one at the top? If so, what is its purpose? Please respond as soon as possible, as I am concerned that I may need to tear the lower unit off One more time. Thanks in advance for any help you can give me.

[angus63]

In 93/94, they did away with the upper drive shaft seal. There is an oring that belongs in the lower section of the drive shaft that sits on top of the pump housing (in the recess). If your driveshaft has the recess about 8" from the top, thats where it goes. I was told it was meant to keep grease in the splined area in place and prevent water intrusion that could oxidize the shaft splines and make removal difficult. Never heard any complaints from those who don't use them. Was there one on the shaft when you removed it??

[angus63]

In 93/94, they did away with the upper drive shaft seal. There is an oring that belongs in the lower section of the drive shaft that sits on top of the pump housing (in the recess). If your driveshaft has the recess about 8" from the top, thats where it goes. I was told it was meant to keep grease in the splined area in place and prevent water intrusion that could oxidize the shaft splines and make removal difficult. Never heard any complaints from those who don't use them. Was there one on the shaft when you removed it??

[angus63]

In 93/94, they did away with the upper drive shaft seal. There is an oring that belongs in the lower section of the drive shaft that sits on top of the pump housing (in the recess). If your driveshaft has the recess about 8" from the top, thats where it goes. I was told it was meant to keep grease in the splined area in place and prevent water intrusion that could oxidize the shaft splines and make removal difficult. Never heard any complaints from those who don't use them. Was there one on the shaft when you removed it??

[angus63]

Holy Cow!!!Never knew I stuttered!!!!!!!

[rdgallo]

Thanks, Angus. To be honest, I don't remember if there was one or not when I took it apart. I had two buddies helping me, and things got confusing at times. I do know I never put one one when I put it back together. My engine is a 1994. I didn't know what the o'ring was for and got worried after we put it back together today and I got to thinking about it. Being a novice at this, I did not want to leave something out that will ruin the engine. I guess I could drop the lower unit again, but hate to fight hooking up the shift shaft again. There must be an easier way to hook it back up. I hope you get your stuttering problem fixed. LOL.

[angus63]

Since OMC did away with it, I wouldn't sweat it!!Enjoy.....

[rdgallo]

Angus, do you know if OMC came up with a different design that took the place of the o'ring or just tossed it? Also, one other thing I noticed when I installed the new pump housing - after sliding it down the shaft and aligning the key and the bolt holes, the housing was actually sitting up a little until I tightened the bolts. I loosened it and inspected everything and everything looked in place. I just figured the o'ring on top of the plate was holding the housing up a little and the bolts would pull it down until the o'ring was slightly depressed. I hope there is nothing else holding it up. I think I just think too much. If you think I did something wrong, please let me know. I started it on muffs in the driveway and everything worked fine. Gears shifted correctly, and I had one good pee stream.Thanks again for all your help. I know I am probably asking some really dumb questions, but just want to make sure that I did everything ok.

[angus63]

If you did not lube the inside of the housing, the friction of the vanes will give you a little "bounce" (1/32") when you seat the housing. As long as a pound or two of hand pressure made it seat flush, all should be swell!! The oring has a recess and should not interfere.

[rdgallo]

Thanks again, Angus. I did lube the inside of the housing with just a little vasoline. It looked like the impeller was just slightly thicker than the old one (possibly wear on the old one?). I didn't really push down on the housing to see how much force it took to push it flush. It was probably about 1/32 of an inch of a gap before I torqued it down.