2010 Yamaha 240SX Shaft seal leak at hull

[Paul Howland]

Last summer, on our last day out, I had a tow rope sucked into the grate and wrapped around the shaft. This year I used a box knife and cut the rope until it all came off. We took the boat out for several days on the lake and had water coming in and the bilge pump coming on frequently. It kept getting worse. Finally, the last time out it was really bad. the water in the engine compartment caused the fuses to blow for both ignition switches.
I did not realize at first that the rope that I pulled out had caused the seal to fail. This became evident when I put it back on the trailer and saw a lot of water running out of the grate area.

I am going to pull the impeller assembly with the shaft, remove the grate and replace the seal. I have never replace the seal in the boat or in the wave runners that I used to have. I will take pictures.

Any suggestions or tips on how to replace the seal?

 

[Cobra Jet Steering LLC]

I will say that is not actually how it is done. I just did one last week and I will be doing another one when my bruised ribs heal from leaning in the hull , I am doing my skies with over 600 hours on them just as routine maintenance, but on a boat the same basic process is necessary, pull pump ,pull engine or in my case I moved it forward to get the intermediate bearing out , replace bearing housing etc " you will need a press to do this and measure the exact location for the inner splined tube and vibration dampener to be installed.
Then put it all back together, first the new bearing housing with the parts pressed in place properly, remember to install the lineup pins also, then the engine and be sure it is exactly where it was when you removed it so don't remove the motor mounts just the top motor mount bolts , reinstall the engine then the pump and check all hoses, I just went out and test drove the one I did last week and everything is fine.
My advice doing the driveshaft seal is not something you should try if you have not done them in the past .

 

[Paul Howland]

Thank you
It’s great to have someone with hands on experience provide the steps to follow.

 

[boudin]

@Paul Howland assuming this is the source of the water leak, take a look at this diagram. Part #4 includes a rubber insert that mates to part #16; this in combination with oil seal #8 form a watertight seal.

https://www.partzilla.com/catalog/yamaha/boat/2010/sx240-high-output-sxt1800dj/jet-unit-2

If you want to save money, you can pull yours and make a determination if the water intrusion is the rubber insert or the oil seal. Or, if you wanted to order parts ahead of time to do the job quicker, it would parts #3 through #9. (though the circlips are reusable)

You will need to pull the pump, loosen the water box connection, all four motor mounts, and then pull the motor forward enough so that you can remove the housing. Then use a shop press to assemble the new housing and press out/press in the shaft. A pair of retaining ring pliers is also needed.

Study the parts in your engine compartment, and then the diagram and it should start to make sense.

Note that we've also seen ropes around the driveshaft crack the angled plastic insert that the shaft runs through where it meets the hull... there is a thread about that somewhere here, but you'll need to search for it.

-Greg

 

[swatski]

Note that we've also seen ropes around the driveshaft crack the angled plastic insert that the shaft runs through where it meets the hull... there is a thread about that somewhere here, but you'll need to search for it.

There have been several threads on this - tunnel dmage due to the rope ingestion and "cocooning" up causing cracks. Here is one:
https://jetboaters.net/threads/repairing-damage-and-a-leak-caused-caused-by-a-rope-being-sucked-into-the-impeller.18078/
I would want to address this first, I think? If the leakage is due to fiberglass tunnel cracks, the intermediate bearing may or may not be damaged/involved, right?

(I'm asking, NOT telling)

--

 

[boudin]

Yes. That is correct.

You can test by tilting the boat up as far as you can, and then filling the back end up with water so it covers the pump tunnel. Look for leaks outside the boat.

 

[Lookingforajetboat]

Yes. That is correct.

You can test by tilting the boat up as far as you can, and then filling the back end up with water so it covers the pump tunnel. Look for leaks outside the boat.

Leak where this shaft connects to the bellows...any advice?

 

[Lookingforajetboat]

View attachment 144046View attachment 144047

Leak where this shaft connects to the bellows...any advice?

The one on the right is nice and clean, the one on the left side leaks and has a bunch of silicone on it...came that way.

 

[Lookingforajetboat]

Looking for this fiberglass thing the shaft goes into on the online parts diagram so I can understand how the two pieces are connected and sealed but the parts diagrams are not clear enough to even find these parts...help anyone?