First water trial run preformance issues with pictures

[Xware]

So finally for my 2004 GTX 4tec 155 on the water after getting it running and when you hit the throttle the rpms jump way up and you can hear the rpms limiting

Here is a quick video where you can hear it.

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Seems to to better once it's on plane .

When running out of the water with a water hose the rpms will instantly jump up to max at only about 10 or 15 percent throttle .

In the water it will max out rpms until it gets going

I looked at the wear ring thru the back nozzle and there doesn't seem to be much of a gap

 

[Xware]

I read somewhere that if you shot a flashlight through and can see white you do need a new wearing here are some pictures To see if the damage to the impeller is extensive enough to warrant replacing it and if you think if you think the wearing is in need of replacement

 

[Xware]

Looking around online it says the maximum clearance should be 0.04" I can slide a piece of cardboard in between the impeller in the wearing that's folded up 3 times and the thickness of it at that point is somewhere between 0.045 and 0.06

So I guess my question is is that bad enough to affect performance by this much?

 

[Xware]

I found my feeler gages And at some places around I can fit the 0.06 between the impeller and the wear ring

 

[skiasylum]

Possibly idle bypass valve and TPS might need resetting? Usually a worn wear ring and or impeller will only cause a loss of performance due to cavitation, not the issues you are having.

 

[Xware]

It kind of seems like cavitating but I'm not sure one once it starts gripping the water it'll go it's just the initial take off the RPM shoot up like it doesn't want to move or it has no power

 

[Lovehamr]

If your RPMs are jumping high enough to hit the limiter, and you aren't going anywhere, you have a pump problem!

 

[Xware]

Well it is moving but when you 1st try to take off it hits the RPM limiter until it gets going on plane and then it's fine But I want to head replace the wearing and the impeller I plan on taking it out for a test in the next couple of days I will post a status update on how it does

 

[Poormanracing]

Wear ring needs replacing its cavitation on launch and when water gets forced in it is loading the pump

 

[MacSeaDoo]

The symptoms you are describing point to cavitation as others have mentioned, the load on the pump is greatest at holeshot.

Personally looking at the photos, your impeller needs to be replaced.

There is a photo there of the leading edge of one of the blades that is greatly distorted. If there is any lip or ridge on the leading edge, it will cause a disruption of the flow causing cavitation. It takes very little distortion on the leading or trailing edge to cause this type of cavitation.

The wear ring is marginal but I would suspect if you replaced the impeller you would see a huge improvement.

If it were me, I would replace both and move on.