Personal Water Craft Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I have a 2002 Yamaha Fx140 waverunner with a Solas impeller.
It used to go about 63MPH until one day when it got a bit sluggish.

This part is important.. on the day that it got sluggish, it would rev to 10,000 RPM and only go 40MPH and then after about 10 or 15 seconds of holding down on the throttle, it would just take off and then start going about 60 or so like it is supposed to. (the sound would also change from a lower pitched sound when to a higher pitch that I am used to hearing) It would then continue to respond normally indefinately until I eased up on the throttle and then it would go back into the slump of only going about 40MPH.

It was almost like a switch or something, the ski would have a lower deeper sound to it and be slower than normal and then after a bit of keeping the throddle down it would then change to a higher sound and just take off and act normally until I released the throddle.

It gradually got worse during the next day or so where it would take longer to kick in, and now it just won't go past 40MPH at all anymore at all even if I hold the throttle down for a long time.

I am curious what the issue could be.

I feel that someone that knows these skis really well can figure it out from my description of the problem and how it started.
 

·
Super Moderator
Joined
·
5,033 Posts
Either it is cavitating bad, or the impeller is slipping on the drive shaft, or the drive couplings are gone. Pull the coupling cover and look to make sure the coupling system is still in tact. If so, pull the jet pump and look at the splines on the drive shaft and in the impeller. If they are ok, check the impeller to wear ring clearance. Also look for any debris in and around the pump intake or in the pump, and inspect the impeller for cavitation burns.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Either it is cavitating bad, or the impeller is slipping on the drive shaft, or the drive couplings are gone. Pull the coupling cover and look to make sure the coupling system is still in tact. If so, pull the jet pump and look at the splines on the drive shaft and in the impeller. If they are ok, check the impeller to wear ring clearance. Also look for any debris in and around the pump intake or in the pump, and inspect the impeller for cavitation burns.
would that cause it to be so consistent in its speed. When it was starting to go, it was very consistent with the 2 speed sets. Either top speed 40 or top speed 63, no in between, just one or the other. And now it's just top speed 40 and that's it. It's not getting any worse or any better. it's almost like an on/off switch was switching from fast mode to moderate mode and now stuck on moderate mode.
 

·
Registered
Joined
·
5 Posts
I just bought mine with 70 hours on it and the first time I rode it mine did that exact same thing maybe twice in 3 miles and then never did it again all weekend. I doubt it's a stripped shaft, once they strip it's not going to hold the pressure of a 60 mph run if the splines are damaged.

Mine felt like a timing or fuel issue in the motor. It was an on and off type of deal almost like pulling a choke and then shutting it off.:dunno:
 

·
Registered
Joined
·
4 Posts
Discussion Starter #6
Is it actually revving high, or just a false reading of the tach ?
That's a good observation, but the ski overall is running slower than it normally did even at lower RPM's. It's like it's exactly 25 percent slower than it was before. Also, I took it out yesterday and it's not getting worse. It's just consistently 25 percent slower.
 

·
Super Moderator
Joined
·
5,033 Posts
If there is excessive impeller to wear ring clearance, wear ring damage, or impeller damage of some sort, it will not hook up. That is the reason for asking about the actual rpm. If the tach is wrong, then you need to look at a ecu issue.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #8
So far it has not gotten any worse, but it is still not going over 40mph any more.
Even if I leave the throttle open all the way for a long time. Its a consistent 25% loss of power. Compression is fine, spark is fine, fuel pump is fine. Engine sounds great and revs at 10k on the water which used to be 63mph. Now 10k RPM is 40mph. I think it may be the pump. Is there an easy way to see if the pump is clogged. Keep in mind how this started (it was 63mph or 40mph at 10krpm no gradual slowdown, just one or the other and now just 40mph. please read my first thread if you want to know the whole story.
Thanks :)
 
1 - 9 of 9 Posts
Top