Cavitating or possible linkage issue with one impeller

[jamin690]

Cavitating or possible linkage issue with one impeller (BENT DRIVESHAFT)

Hey All,

Last year I took a rope pretty bad and had cavitation issues afterward. Before putting it in this year I had my impellers remachined by impro's and bought new wear rings. While I was doing all this I had not noticed any bent drive shafts or major cracks in the jet house veins, however, after putting the boat back in the water I found that the same motor that took the rope and cavitated afterward is still doing this. At one point yesterday this motor even seemd to spin freely almost with no resistance from the water. The boat will still get up and get to almost full speed, but one engine is definately not doing all it should and you will see the RPM's bounce as it seems to loose traction with the water. I am wondering if this could possibly be anywhere along the drive sharft that has a linkage and may be slipping. I am going to pull it out of the water next week to try and fix it, but right now I am puzzled at what could be casueing this since the impellers and rings are new.

Any thoughts are welcomed, I realize that it could be alot of poissiblities causeing cavitation but this just seems extreme without any noticable damage.

 

[jamin690]

Corrected post.

Removed this item

 

[jamin690]

So I have finally pulled out my boat to try to resolve this on going and kind of drastic cavitateing on one engine. Looking with a flashlight into the inlets everything looks fine on the entry points and through the channel towards the impellers. I did notice that the plastic sheeth that goes along the shaft if gone on the motor that cavitates, the other engine only has half. I have read here before that the sheeth is not really all that important but I'm not 100% sure and if someone could confirm that it would be helpful.

I am going to look more at the drive shaft while its running to see if there is any vibration perhaps thats causeing turbulance here as I think thats what causeing this cavitation.

 

[jamin690]

The Drive shaft has a bend in it.

Well, I looked up through the water intake for the jet and noticed there was vibration at the drive shaft. I compared to the other engine which was of course, smooth and completely in line. If I had to bet, I would think this was my cavitaion issue.

So I am starting to take that side jet off again, but I am really puzzled on how I will remove the drive shaft. I can't seem to locate any material in the manual I purchased (onwers manual and parts list). Right now I am worried that the engine might have to be out of the way so the drive shaft can come in through the boat? I really....really hope this isn't the case.

As always, any thoughts or suggestions are appreciated.

 

[jamin690]

I just saw some input on how top remove this from a 96 Sportster, I will assume this is more than likely similar and see what I can do. I have remove the pump but it looks like I may have to put it back in to remove get the shaft work done.

 

[gcha1727]

I just removed mine from the 787 motor. Im not sure which motor you have. If they are smilar you will see a silver ring on your drive shaft in eng comp. It buts up to a carbon ring and rubber boot which is flexable. Push the silver ring towards the back of the boat and remove the circlip under it. after that it will pull apart easily.

 

[jamin690]

It is a 787, thanks for info, I will look into this tomorrow!.