Bowser's WaveRunner

Thermal differential is the key. Unless you have dry ice or liquid nitrogen, you'll get about 100 degree differential at most cooling the shaft. But heat the bearing up (not ones with plastic shields) to 300 degrees F in an oven or an air fryer, now you are talking a 400 degree F differential. I've also heated bearings in cooking oil in a pot with candy thermometer when I needed to install it at the other end of the house in the garage. Work fast and it will drop right on.
Thanks for the suggestion too ‘Mac.


I sheered off the hose barb to run water through the motor. Literally no effort sheered it clean off…
Can’t seem to get extractors to extract the residual metal stuck inside- merely reaming it out.

SO I could JB weld the broken piece back onto the fitting or buy a replacement exhaust cover with hose bard intact for ~$30.
I think I’ll try my luck JB welding it back together since it’s not a high pressure/ heat situation.
_ _ _ _

I have a couple more gaskets to order and the bearing for the driveshaft but it's mostly coming along.
"it’s not a high pressure/ heat situation" Correct, it is the weight of the hose and vibration situation. Are you OK with the failure of a water hose inside the hull? Is the water flowing into the engine where a failure would overheat the engine or is it an outlet that would pour water inside the hull? I do not trust JB weld unless the failure mode is benign.
Brian thanks for the considerations- I would indeed want this to be a solid fix for a long time w/out worrying about engine overheating if the JB weld fails.

Just drill and tap for a standard NPT brass hose fitting.

This is a much better idea, thanks 'Mac! I'll proceed by finding a replacement brass hose fitting.
Another step forward another hurdle appears.

I pulled off the pump assembly to access a few things needing repair; the impeller blades, pump cone, and broken assembly bolts. That bad boy was really corroded on- I hooked it all up to a winch and cranked on it while smacking it off with a mallet.


Now I'm stuck with the studs embedded in the assembly, shown above. I tried vice grip + P.Bizzle unscrew them out with no luck. Extractor drill bits are worthless too. Also cut a slot in the top and unscrew with a flat head blade with no luck.

SO either I trailer it to the pros to have them remove the broken bits or pull the whole b!tch out and replace everything I can. Both options comparable in price. The pump cone and stator vane component are really stuck on which makes me want to throw it all out and start with something I can actually access. The impeller seems to be held hostage ..

All this effort and the drive shaft coupler is still stuck?? I really don't know why it won't spin- there's no driveshaft in it where I though the problem was. I can't imagine having the motor in the hull engages it some how. I may have to take this Q to a Yamaha specific forum o_O
I thought about you a couple weeks back while working on trailer bearings. It started off with a plan to replace just the seals and repack the bearings. But one bearing looked sad so I decided to replace all bearings. I got the outer cups out of the hubs using a TIG to shrink them. New cups went into the freezer and the hubs into a 300F oven. The should just slip in, right? Wrong. The relatively small mass of the cups vs the large mass of the hubs allowed me to get the cups in about a 16th of an inch before they heated up and stopped. But at least they got started and I tapped them in the rest of the way. The job is always easy for the person not doing the work. Even though I am not working on your ski, it looks difficult to me.

I bought a pair of WR500’s with trailer. :D

Both have everything intact aside from a broken hinge on the hood and shredded seats. It’s neat to see the differences between my first cough abused cough WR500 and these two stock models. I paid $450 for it in total which is easily what the trailer alone costs.
Tested the compression on one and it came back solidly 150 psi both cylinders!
I would test the other’s motor but I snapped the spark plug off in the head -___-

SO I’m going to hustle to get the carb I restored last summer on the working motor and fire it up!

Here's the chosen WR500 with good compression, good fuel suction, but will not fire.

Spark tester checked out fine- albeit hard to see in daylight.
Fuel filter shows plenty of fuel available, primed cylinders + carb too
Starter spins it all well
Motor just won’t spark the fuel, in all the attempts it never fired a single bang or puff

I guess next step is to swap out the CDI ?