Cavitation?

[ImpulsiveJames]

Is this impeller too damaged? I get about half - 3/4 throttle, then it doesn't seem like anything extra. I think I'm missing about 10 MPH.

 

[ImpulsiveJames]

The weird thing is it's not hitting the rev limiter, and it isn't bogging either, it's just like there isn't anything there

 

[ImpulsiveJames]

Sorry, 1994 GTS with the 587

 

[ImpulsiveJames]

Ok, so I just took it back out, it is hitting the rev limiter, so that means impeller or wear ring most likely, correct?

Depending on what you guys think about the impeller, I'll get a wear ring on order. I thought I checked the clearance correctly, but I probably did it wrong.

 

[NickCawks]

That impeller is definitely beat up

 

[Sandman251]

You should remove that impeller and take a file to all the burrs. You could try to tap out any of the remaining irregularities. There will be a huge difference, I assure you. Also you are missing the impeller boot. It attaches to the impeller and slides over the drive shaft as you install the pump assembly. It helps to hold grease on the splines of the driveshaft.

 

[ImpulsiveJames]

Thanks! I'll give that a try!! I'll also look into getting a boot before I put it back together!

 

[ImpulsiveJames]

Found a few interesting nuggets...

For one, how the hell did the last person bend the rear of the impeller????

And two, this has a 271000046 impeller, I think it should be a 271000299. I am working on a 1994 GTS after all.

I can probably fix the impeller, but is there any benefit to this XP impeller, or should I put the correct one in?

 

[ImpulsiveJames]

Answered one of my questions, the 271000046 was an optional SS impeller for all models pre 1997. I'll try to bend it out, clean it up and give it another shot

 

[AKnarrowback]

That impeller can be saved.

The trailing edges bent forward are from material/rocks going through the pump and getting caught between the rear of the impeller and the leading edges if the pump veins.

Put the impeller in a vise and gently work the trailing edges back to their, close to, original angle. The leading edges bent forward are robbing you of that last bit of throttle and allowing you to over rev and hit the limiter.

Take a file to the leading edges, I use a small angle grinder, and make them straight out from the center hub again. After they are straight then file/grind a new leading edge like a knife.

The blunt leading edge is robbing the hole shot, trailing edge is robbing the top end. This is why you are feeling a loss all around.

If your liner is gouged or damaged then get a new one.

A slight bend in that trailing edge can change your top rpm's. The 92 xp's had rev limiters that drifted a hair and caused a perfect impeller to bump the rev limiter. The fix was a new rev limiter (money) or a slight bend back of the trailing edge (free).

 

[ImpulsiveJames]

Thanks for all the insight. I bent the one trailing edge that was really bad and ground the leading. It probably does need a new ring, I was hoping to get it out and test today.... Maybe I'll have to wait

 

[ImpulsiveJames]

Guess I should post some pics.

Not perfect, but it's def better

 

[AKnarrowback]

Get the leading edges straight, the entire face is jagged still. Get one flat face, as viewed from the top, then put a nice sharp edge on it.

 

[ImpulsiveJames]

K. Thanks. I was just worried about removing too much material

 

[mikidymac]

It might get you by but the correct way to fix it is to send it to an actual impeller repair shop like Impros. They will make sure the outside diameter and all blades are set to spec and balance it.

 

[ImpulsiveJames]

Hmm.... Yeah, $125 isn't bad, I'll see how this runs and consider it. Thanks!

 

[AKnarrowback]

If you have the money then get it done right. Send it out to be rebuilt properly.

 

[POPPS]

AK, has good advice, I take a cold file, and then file the entire length of the prop, till it is flat, then I file out any burrs,,I use an adjustable wrench to bend the blades to closest pitch as possible.