Yamaha T-8 and 9.9 Water Pump Rebuild

[huntnphool]

 I had to rebuild the water pump on my Yamaha T-8 kicker engine so thought I would do a step by step tutorial for those that prefer to do their own wrenching.

 You will need a rebuild kit, which I purchased online at http://www.boats.net/parts/detail/yamaha/Y-69G-W0078-00-00.html

 You will also need a couple 10mm open end wrenches, a 12mm wrench and 12mm socket/ratchet combo if you want to speed it up a bit. Some people use anti sieze but I have found this to cause more trouble than good so I prefer to use "Corrosion Block" grease, it works very well.

[huntnphool]

 You will need to remove the lower unit of the engine to access the pump, the first thing you do is locate the gear shaft. It is located in the front of the engine about half way up.

 Holding the top nut with one of the 10mm wrenches, turn the bottom nut (lock nut) clockwise with your other 10mm wrench.

 Once you unlock the two you will need to turn the top nut counter clockwise. Losen it a bit and leave it for now.

[huntnphool]

 Next, locate the four 12mm nuts that hold the lower unit on, they will be located two on each side just above prop. Using your 12mm wrench, remove the four nuts and lock washers, be careful not to let the entire unit just fall, remember your gear shaft is still attached and you dont want to bend it.

 Once the four 12mm nuts are removed you want to lower the unit a little and turn the upper gear shaft nut counter clockwise until the shaft is seperated. Once this is done you need to remove the gear shaft lock nut.

 The lower unit will now seperate from the upper engine. If it does not slide off by itself tap down on the fin of the lower unit with a rubber malet, its likely just dirt and corrosion on the bolts hanging it up.

[huntnphool]

 With the lower unit removed you will see the impeller housing. Start by removing the rubber boot, it will pull off.

[huntnphool]

 Next use your 12mm socket or wrench to remove the four bolts holding the housing on, once they are removed you can slide the housing off of the drive shaft.

[huntnphool]

 Once the housing is removed you will see the impeller, or in my case what is left of the impeller. This is what happens when your buddy doesn't realize that you need to hold the kill switch down until the engine stops, not just push the kill switch and lift the engine out of the water.

 The plate has the new impeller on the left and whats left of the original, notice all the pieces that were clogged in the housing.

[huntnphool]

 Now you need to remove the remaining two 12mm bolts that hold on the plate.

[huntnphool]

 With all the bolts removed you will now need to locate the pin that is pressed into the drive shaft. I forgot to take a picture of it but it will be very easy to locate, it is the piece that will not allow the plate to slide off the shaft. The picture shows what it looks like when you get your rebuild kit.

 It is snug but will come out of the shaft if you pull hard enough. Once its removed slide the plate off the shaft, clean the housing, washers and lower unit.

[huntnphool]

 On the inside of the impeller housing is a aluminum shield and O-ring, remove the O-ring and shield.

[huntnphool]

 With everything cleaned its time to assemble the unit. Insert the new shield into the impeller housing, grease up the housing and O-ring and insert the O-ring into place.

[huntnphool]

 Grease up both sides of the new impeller, the shaft and slide the impeller down into place, making sure that the impeller fits onto the shaft pin. It doesn't hurt to add a little grease to the plate that the impeller sits on either.

 Now slide the housing on the shaft and over the impeller, you will need to turn it as you do this to get the impeller into the housing. It doesn't look like it will fit but it does.

 Grease the holes, new bolts and tighten. Put a little grease on the rubber boot as well, it will help it slide into place.

 Lift the lower unit into place, the drive shaft may have to be turned slightly with the prop to get the splines in line. As you lift it into place the first thing you need to watch is the rubber boot, it must slide over the hose inside the upper unit.

 Next re attach the lock not to the gear shaft, turn it clockwise to the bottom. As you lift the unit make sure the gear shaft aligns with the upper nut, turn the nut clockwise to attach to the lower unit gear shaft. Lower until approx where it was before, now turn the lock nut counter clockwise and tighten up against the upper nut with your 10mm wrenches.

 Lift the lower unti the rest of the way into place, lube the mounting bolts and nuts and tighten with the closed end of your 12mm wrench.

 Hook up your dog ears and hose and fire it up, you should be pumping water again. If the pee valve is not working but you see water coming out of the upper case then you don't have the rubber boot over the internal hose. You will need to drop the unit again and make sure the boot is in the right place. Tight lines!!! 

[MtnMuley]

Very nice phool.   If I ever have to do my T8, I'll definitely remember to look up this post.

[Wacenturion]

Nice write up. 

Again....another great narrative....Thanks.

[NRA4LIFE]

Speaking of T8's, has anyone ever experienced the tiller handle seizing up?  I would really be interested to hear how you fixed it.

[wildmanoutdoors]

Nice write up! I have done mine twice now.

I started the fuel pump rebuild last night. Maybe we should have a DIY forum?

Before and was leaking...