Re: 25hp NissanTohatsu Water Pump Replacement
I couldn?t find any good how-to information on the Internet on replacing the water pump on small Nissan-Tohatsu outboards, so I went to the my local Nissan-Tohatsu Marine dealer (Weeds Marine, Lexington, SC) and the owner there was nice enough to give me some pointers when I bought the replacement water pump impeller. It wasn?t difficult to do; it took us about 3 hours to change the water pump, the fuel filter, the engine oil & engine oil filter, the spark plugs and the gear lube in the foot.
The water pump gave me some concern because I?d just purchased the outboard and I?ve never done one before, I?d seen it done once on a large outboard, but I?d never personally changed one. I?m sure glad I did it though, there were only 2 fins still intact -- that water pump impeller was destroyed! Hopefully this will help someone else that may be facing the same problem. Here is what we did, step-by-step.
Pay it forward, right?
Tools We Found Helpful:
A small set of sockets/ratchet, a crescent wrench, a very small punch, a hammer, a tiny flat jewelers screw driver, shop towels, WD40, marine grade waterproof grease, resealable sandwich bags and a sharpie.
STEP 1. We disconnected the fuel line, the (+) positive battery terminal, and pulled the tab from the emergency-stop switch just in case. We figured if someone accidentally mashed the starter button we'd both still like to be able to count to 21.
Step 2. We raised the engine as high as we could so we could reach everything conveniently without (getting old!) stooping too much.
Step 3. We removed the four bolts that hold the foot onto the engine, bagged them and tagged them with a sharpie.
http://www.energyenforcer.com/users/jake/STEP-3.jpg
Step 4. We put the engine in neutral where we could get easy access to the shift linkage keeper pin. We took a punch and drove that pin out being careful not to bend it or lose it. I think it would be really easy to lose that little sucker while driving it out. We drove it from right-to-left but I?m not sure it mattered. We took a sharpie and marked the side of the pin that we drove from to make sure it went back in the same direction, again, not sure if that matters, but just in case. We bagged it in a separate zip-lock bag as well.
http://www.energyenforcer.com/users/jake/STEP-4.jpg
Step 5. The last thing holding the foot onto the motor was a single nut (and washer) right on the front of the engine directly in front of the shift linkage. We had one person holding the foot so it didn?t slide down and damage the shift linkage while another person removed that nut and washer. We bagged them along with the keeper pin from the shift linkage.
http://www.energyenforcer.com/users/jake/STEP-5.jpg
Step 6. We pulled the shift linkage forward (just slightly by hand, very light pressure) and the linkage came apart. After we separated the linkage, the foot slipped right off the engine with no effort at all.
Step 7. We soaked the 4 bolts on top of the water pump housing in WD40 and cleaned them with a very soft wire brush. We broke them loose with a star pattern and the housing cover slid right up the shaft revealing the water pump. I kind of wish I had purchased a new paper gasket as well, but the mechanic there said as long as there was no damage to the existing one I would not need it. The gasket was still in good shape so I just cleaned it up with a dry paper towel and reused it. Next time I do it I will be sure to order the whole kit.
http://www.energyenforcer.com/users/jake/STEP-7.jpg
Step 8. There was a small pin, which locks the water pump impeller in place on the shaft. We cleaned it and bagged it. We also took a damp shop towel and cleaned out all the little bits of rubber and gunk from the water pump housing. We had to take a small jewelers screw driver and dig a tiny ring of rubber from the very bottom of the shaft that had gotten down in there (much like fishing line gets in the propeller housing). It looked like a rubber seal at first, but on closer inspection it was just junk from the messed up impeller that got smushed down around the shaft.
http://www.energyenforcer.com/users/jake/STEP-8.jpg
Step 9: We replaced the water pump with the new one and reinserted the locking pin. We spun the shaft as we slid the housing into place to make sure everything moved freely and nothing got hung or bound up in the process. We put a light coat of oil on the threads of the 4 bolts that hold the housing in place and tightened them with a star pattern.
http://www.energyenforcer.com/users/jake/STEP-9.jpg
Step 10: We put a thin coat of water resistant marine grade grease on the shaft. We also put a little heavier application of grease on the top 4? of shaft where it slides into the engine itself.
http://www.energyenforcer.com/users/jake/STEP-10.jpg
Step 11: We slipped the foot back into place, we had to do this twice because the shift linkage was a little funky. It did not line up correctly the first time. The trick to this was to just manually pull the linkage all the way up. (There are three positions, Up ? Neutral ? Down) and when we slide the foot back into the engine, we left about ?? gap between the foot and the rest of the engine. That gap gave us plenty of wiggle room to manipulate the shift linkage back into place.
http://www.energyenforcer.com/users/jake/STEP-11.jpg
Step 12. We replace the 4 bolts from step 3 that hold the foot onto the engine and tightened them in a star pattern.
Step 13: We took a tiny flat jewelers screwdriver and (very gently and very lightly) spread open one side of the linkage keeper pin (just slightly) to make sure it stayed nice and snug when we drove it back into place. We didn?t spread the side that had sharpie mark on it because we wanted to drive it back in the same direction and orientation it was in when we removed it.
http://www.energyenforcer.com/users/jake/STEP-13.jpg
Step 14: We gently drove the keeper pin back into the shift linkage and replaced the nut and washer from step 5.
Step 15: We went back over all the linkage, testing that it still engaged properly and it smoothly changed through all three positions (up-neutral-down)
Step 16: We reconnected the (+) positive battery terminal, the fuel line connector and the clip for the emergency stop switch.
Hope it helps someone down the road.
Jake A.
Lexington, SC.
P.S. Mucho thanks to Paul for the condensed version, it was really helpful!
