Yamaha SHO/SVHO Impeller Removal- removing the stock Yamaha impeller

[K447]

I imagine similar threads have been posted previously, but I did not find one suitable to add my own thoughts. If there is an existing thread I could add to, please point me towards it.

For the time being, here are my comments and suggestions.

The Yamaha impeller is threaded directly onto the drive shaft. The entire drive shaft must be removed, then the impeller can be unscrewed (perhaps with prejudice) from the drive shaft.

To remove the impeller, first you must remove the jet pump steering nozzle assembly. Disconnect the control rod for the RiDE bucket. There is a slide clip on the rod end that when moved against a small spring tension will release the ball end. Do the same for the trim rod end.

The steering rod has a 10mm jam nut on the bottom. Remove the nut, then unscrew the shaft from the nozzle arm.

Slide the spring hose clamp up the tube for the bilge siphon, then wiggle the rubber tube off the nipple.

If the 'visibility spout' short hose is still in place, disconnect it from the top of the jet pump.

There are four bolts holding the jet pump nozzle assembly to the jet pump. And another two bolts holding the bracket above. Remove all six bolts. Take a few photos before you start and more as you go, to be sure you put everything back here it came from.

There will be factory sealant between the nozzle and the pump stator. Find the small pry blocks at the joint/seam and carefully pry there with a flat screwdriver tool until the sealant lets go and you can extract the steering nozzle assembly. Set it aside.

Now you can work to break the next stage of sealant grip and then slide the jet pump stator+impeller assembly out.

With the drive shaft out and the impeller assembly still attached to one end, we can work to remove the impeller.

Tip: Do not even attempt to remove the impeller using any sort of open ended wrench. The hex shape on the nose of the impeller is NOT like a big nut. It is a very thin walled casting. You will damage and distort the impeller hex if you use anything other than a six point box end wrench (in my opinion).

Do not even think about using one of these.


This is what is needed. Six point box end wrench, size 1 1/16".
Since this is a metric watercraft, there is a probably metric mm wrench size that should also work. It was easier for me to find the 1 1/16" size than the metric version.

It may be possible to use a 12 point box end wrench but I felt there was significant risk of rounding off the impeller hex or even ruining the impeller entirely. I wanted it to come off with minimal damage, on the first attempt.

Slide the box end of the wrench down the driveshaft and onto the impeller hex. I oriented the wrench angle to lean towards the impeller blades, not towards the drive shaft.

It may be necessary to use a hammer to nudge the wrench onto the impeller hex and get it fully settled. You really want the tool fully seated, to avoid damaging the thin metal.

You will also need the special ‘Tool53’ HO/SHO/SVHO shaft holding spline tool to hold the engine end of the drive shaft.



I used a six point socket (1 1/8" size?) and a long breaker bar with 1/2" drive to fit the spline tool. 3/4" drive socket would be even better. With the box end wrench in position on the impeller, slide the spline tool, socket and breaker bar onto the driveshaft end.

Lay the driveshaft on the ground, parallel to your car or truck tire. Position the end of the breaker bar just under the tire, then roll the tire enough to fully trap the tool against the ground. You really want the tool to not move, as you will soon be applying serious torque to the impeller to break it free.

I used a five foot long threaded well pipe section (sold at Menards and elsewhere) as a cheater lever on the impeller wrench. The open end of the wrench was too big to fit inside the pipe, so I ground off enough metal to allow it to fit, just barely.

[K447]

Note: The Yamaha impeller has LEFT HAND threads.

To remove the impeller, you will be turning it in the same direction as it spins when running in the water.

Position the wrench on the impeller so you have a good angle to lever relative to the ground, then slide the long pipe onto the wrench.

Tip: You don't want to be pushing the long pipe towards your car. Set it up so you are pushing the pipe away from the car, angled towards the ground.

Recheck that you will be applying pipe+wrench torque in the correct direction to loosen the impeller. Left hand thread.

Brace yourself, and apply force to the pipe to turn the impeller. The driveshaft itself will wind up with torque, keep levering the pipe to increase torque as the shaft twists. Hopefully with enough torque applied you will hear and feel a 'pop' as the impeller finally begins to break loose.

Some of these impellers can be really stuck in place. Even with the long pipe leverage it may take some grunting and commitment to break the impeller free.

Once you feel/see/hear the impeller begin to move (in the correct direction), continue to apply motion to the pipe and soon the impeller will become quite loose on the threads. Brace yourself so you do not stumble when the impeller lets go.

Remove the long pipe, then roll the car tire off the breaker bar and disassemble the tools. You can tap the box end wrench off the impeller while it is still threaded on the driveshaft. Then unscrew the impeller.

[K447]

These two videos show much of the job but each has moments where they get it slightly wrong or skip over something.

Putting the driveshaft tool in a bench vice may not provide enough strength and stiffness to allow you to actually torque the impeller loose. I have read reports of people even breaking their vice.

[Quinton Robbins]

I've got a Skat impeller on the way for my GP. I'm somewhat dreading the swap.

However I'll also be installing the dual washer setup so perhaps future changes will be easier. I'm surprised I've not seen videos or posts about people adding the washers to prevent future issues.


R & D Yamaha Low Friction Dual Washer Impeller Spacer 2008+