At the beginning of this season the water pump impeller blades disintegrated. I managed to drop the bottom part of the outboard and remove the top of the water pump body. I needed at least a new impeller and the short plastic pipe that connects to the copper tubing going to the engine's water jacket. The dealer talked me into a complete kit. I don't see how to pull out the bottom half of the pump body. I know from examining the new one that there's an 'o' ring at the bottom. Is it just a matter of brute force?Most of the parts in the kit I can account for (new shaft key, top seal, etc.) There's a very small metal washer and two more rubbers. One's an O ring (smaller than the drive shaft dia.) and another rubber ring. Will it be obvious when I pull out the other half of the pump body? (I know - I should get a manual :- 0 ).Thanks,MiYotie.
MiYotie,The best way to remove the water pump base is to gently pry it out with 2 pry bars. Be sure to use a protective pad under the pry bars so you don't damage the gearcase housing. Hope this helps!
Sooo - the bottom half of the housing came off OK. Thanks.The kit came with more pieces than I can account for. There was nothing like them when I took everything appart. Either the last guy didn't do it right (it was done up in the North Channel as an emergency repair) or the kit has more parts than I need.There are two fiber washers. Blue - 9/16" and grey = 3/8".And there's a plastic ring, stepped - 5/8" outside. The dia. is smaller than the drive shaft. It would fit in the side of the pump where the rubber sleeve (with a little nub) goes. But why? Good that I changed the whole pump. The bottom bearing is kaputt.The impeller is much bigger than the pump inner dia. but I thinki I read in another post that that's normal.MiYotie
Post Script:If anyone's interested (but still no substitute for a shop manual :-) ), here's what I learned...The kit was 46-70941A 3The stepped plastic ring (not on Mecury's micro-fiche and not in my old pump) seems to be to protect from pushing the intake pipe too far into the body of the pump. I put it in the hole in the side of the base, before the rubber sleeve. It's deep enough.The larger rubber ring slides down on top of the pump top. The 'O' ring stays at the top of the drive shaft, just below the splines.It would have been easier to leave the gear shift in forward (one set of instructions I read said reverse, but maybe that was for a different motor or different (left vs. righ rotating) prop.) That way the motor tilt interlock isn't a problem and you can turn the prop without it popping out of gear. Forward is when the selector shaft is fully clockwise, when viewed from above. I had to jiggle the gear shift a little and turn the prop to get all the splines to align and slide into place.The fibre washers are for the gear drain and overflow screws.I tested it in a barrel. May have to fine tune the gear shift and tilt interlock after a test on the water.MiYotie.
Hi MiYotie, I have a question concerning the O-ring. When I replaced the impeller and put it the lower unit back on, I was getting water in the carb. I didn't know if I did something wrong, so I took the lower unit back off and there was a o-ring laying at the bottom. It seams too big for the long shaft, but I wondered if it even goes there. Can you tell me where the o-ring goes. I have a 1983 Mercury 7.5. I just got the boat and motor. Is the mixture 50:1 for gas. And do you think me having water in my carb have anything to do with the o-ring missing where it goes? Sorry for all the questions, I am new and this site really is helping a first time boat owner. Thanks
Hello Drobel83, welcome to the board. I have been reading post, and yours caught my attention. I had the same hp and year model on my duck boat. I parked it at the end of one season, and when I got it out for the next season, the water pump was out. Changed the water pump, every thing worked fine. Wish I could tell you more, but I cant. I will offer a word of advice You should take the motor back where you got it, and invest in a good trolling motor. I have found that a trolling motor is much lighter, quiter, and econonmy fuel efficiant. I hope this helps.Brandy Ritton aka Catfish131313
Hey Catfish131313, I have a trolling motor. Having a Mercury 7.5 motor would be more convenient in moving around the lake when I'm getting out of the rain. That's my kinda luck.I would'nt want to get struck by lightning.Hopefully I can get the motor running, someone told me water in my carb is no good at all. I did check out a diagram of lower unit which included the water pump and it looks like that part of the problem may be repairable. Just can't figure out the water in the carb issue, may be that the motor was used too much with the impeller out and it burned out the motor. Hopefully not, but it sure is looking that way.