Rubber Shaft Coupling - anyone replace?

[YamahaCC]

I am starting to suspect I might have a rubber shaft coupling that has failed, has anyone replaced this before? Not so much looking for a 'how to', just wondering how common it is and/or symptoms that lead to it being replaced. Part #1 on the diagram below. Thanks!

 

[Scottintexas]

That is an extremely rare part to replace
I’ve maybe remember 1 other member doing that

what makes you think that’s a problem ??

 

[Cobra Jet Steering LLC]

intermediate bearing and or pump bearings are the norm

 

[YamahaCC]

I have heard the bearings are a lot more common. I posted a thread about an engine rattle before so I installed new plugs and coils and took compression (which all were equal and strong per the service manual). Oil is clean and proper level. I hauled the boat and had my tech pull the pump and everything looked fine. We ran it w/o the pump and there was a very slight improvement, but not much. The noise is a lot worse when the boat is in the water and there is pressure on the system from the impeller turning. Engine turns up right were is should as well for RPM but at idle it is very noisy comparted to the stb when for years they were both very smooth and quiet:


stb engine first then noisy port - this is a follow up from my prior video.

I took it out for an hour of watersports after the above work and at the end of the day the 'rattle/noise' has gotten louder. You can hear it in the video as well, but in person it is a lot more dramatic. I wonder if it is the rubber coupling as that would explain the metal noise' if it has failed and it would explain a bit why it would be louder in the water with pressure on it. Once you increase the RPMs the noise reduces a fair bit.

 

[Scottintexas]

Once there’s constant pressure it should stay firm against the coupler unless the rubber was so compromised it was skipping over some of the compromised flanges

I’m not making the connection for the rubber

maybe the intermediate bearing??

 

[Cobra Jet Steering LLC]

ok remove the grease fitting from the intermediate bearing housing or in your case they probably have a hose that is on a hose barb at the housing . Use a piece of weed wacker plastic string and slide it into the intermediate bearing housing and then remove the string so you can get a look at the grease in it, if it shows water or discolor it is bad and you will need to replace it, you can also inject gear lube into the housing directly using a plastic dental syringe and put it in where the hose barb is just remove it and then return you are when you finished. I have dons many posts about adding automotive gear lube to the intermediate bearing and the pump grease. I believe you have an issue with the bearing I have put over 1000 hours on the vibration dampener between the engine and drive shaft with no issues you should be able to rock the impeller back and forth with a clunk or some play if that piece is bad You may also not have the motor mounts aligned perfectly or a bad mount. If you add the gear lube and the intermediate bearing is bad it will usually start leaking the gear lube inside the boat indicating that it is bad .

 

[HawaiiBreeze]

On all my Yamaha and Kawi PWC's and all the ones I worked on while a mechanic at a shop I only saw 1 of my own and 1 other from a customer wear to the point of replacement. If you want to know more before pulling the trigger on the job get a rag down there and see if it comes back with rubber dust and or pieces. Finally drop a camera phone on video under the coupler, take the plugs out, turn the shaft by hand from intake grate side and see what you find.

 

[Hoppy]

I am starting to suspect I might have a rubber shaft coupling that has failed, has anyone replaced this before? Not so much looking for a 'how to', just wondering how common it is and/or symptoms that lead to it being replaced. Part #1 on the diagram below. Thanks!
View attachment 206696

You should be able to remove the coupler cover and see if there is any significant play between the coupler halfs and parts of the rubber for an inspection. I replaced one twice on my lx210 the first one I put in with a reman engine was badly worn from the engine being misaligned previously. The second was the new defective aftermarket rubber started loosing pieces of itself after a few hours of use that I found in the bottom of the engine compartment. The new new aftermarket one is holding up good. If yours had failed I would suspect you would find chuncks of rubber in your engine compartment also.