[amissner]

Round 2.

I thought maybe my ski was missing at low RPM and the misses were resulting in some mechanical noises in the engine. Drained the gas and put in fresh gas with absolutely no improvement (if anything it is now worse), so that eliminates the fuel at least.

I have run it with a flush kit so I can get a little closer to the engine and I believe I am hearing a mechanical noise from the impeller area. What felt like misses could be binding I suppose. It does work fine at high RPM and has not lost any top speed.

Could this be a symptom of the impeller rubbing against the wear ring? Can this occur with only 72 hours? Tips for further diagnosis?

Thanks in advance.

 

[Ernest T]

Is your ski the VX110 (4 stroke) or the 2 stroke XLT1200? If it is the 4 stroke, there is a normal rattle from the drive assembly at idle. This noise us usually worse out of the water on a hose, but nothing to worry about.

It is possible to have damaged the impeller if something ran through it (I've sucked up fishing line, sticks, and a fish without damage so far). If you have small hands and a feeler gauge you can pull the plugs and check the clearance. I doubt it is rubbing or you would see a loss of power.

Here is a video of an FX140 that demonstrates the rattle that is common on Yamaha 4 stroke skis:

If yours sounds like this..........nothing to worry about. If different............possible problem.

 

[amissner]

Awesome video, thanks

So, I am fairly sure the rattling/grinding noise is just the "normal" noise since it matches your YouTube video.

I guess that leaves the mystery of why it is missing with no apparent loss of power. If I am not concerned about breaking something mechanical I guess I can ignore it for a while.

I suppose no harm in replacing the plugs either. They are probably 5 years old.

 

[Ernest T]

If you got 5 years out of those plugs you really got your moneys worth. It is not a bad idea to pull them out once every season inspect them, and clean them up with a wire brush. It also helps prevent them from becoming seized in the engine.

 

[Ernest T]

Also, I thought I'd mention that if you are doing your own maintence you may have missed several recall notices for the 2005 model VX:
http://www.yamaha-motor.com/waverunner/fmc/factory_modification_letter_WR2008-001R.pdf
http://www.yamaha-motor.com/waverunner/fmc/factory_modification_letter_WR2005-009R.pdf

If these things haven't been fixed, I'd take it to a dealer and have them taken care of (Free even if you are not the original owner).