Thread:

Impeller sizing and repair questions!!

Well I started taking my pump apart tonight which is insanely easy since these things are so simple. I took a few pics. The leading edges on the intake side are rounded and beat up but the back side of the impeller looks pretty good from what I can see. What is the proper way to clean up the impeller? Do you only smooth it up and grind from the top side without touching the bottom side of the edge? Here is what the impeller looks like on both sides and also some pics of the stator which looks a bit beat up also. Let me know what you guys think. It looks like it is a B impeller and says aggressor mb401 on it....which doesn't mean a lot to me maybe someone can chime in....its an 18 ft baja with a 402 bbc near stock, with this je pump and has a place diverter, turns 4600 rpm and does only 45-49 mph depending on how many ppl are in it which seems a little slow to me...according to the impeller chart its making 300ish hp. Is this the right size impeller for the boat? and would a loader thats set up right help my boat out any?

Here is the intake side.... I need a bigger wrench to get the impeller nut off so this is the best I could get of this side so far but it looks like it should be fixable


Here is the backside of the impellar, it has nice crisp edges



Here is the inside of the bowl.... does this stator look ok or is there anything to do to clean it up a bit?



I am going out of town for the weekend and I will get a wrench to fit the nut to get it off and I am getting a larger diameter caliper to measure the impeller and wear ring to check clearance, just by moving the shaft by hand it seems like its a little sloppy and not in tolerance which could most certainly be adding to the problem. Ohh and some more info... when u floor it the nose likes to come up and just doesn't seem to get on plane real quick at all even with the diverter trimmed all the way down to start.



Sorry for all the questions but I'm new to these jets and any help or suggestions are appreciated! thanks in advance

Anyone sharpen the impeller blades? Curious on how to do it properly.

Well there's no doubt I have found a lot of the problem......I check the tach with another one hooked up and it reads spot on....So i got the impeller out and here are the measurements I found

In pictures

impeller sizing-7.218 was the norm...this was a little smaller spot.


Wear ring-really bad 7.36



Beat impeller blades


You can see the wear in the ring




Well that's it for tonight...figured I'd post my findings since they are most certainly interesting.
Jeff at jetperformance thought it was weird the wear ring was so worn but the impeller was close to being in tolerance.....but who knows what the PO did to it before I bought it because all the seals and grease and bushing in the end of the bowl look like they were just replaced.... maybe put a new seals impeller and all but overlooked the wear ring? ya never know but at least I found a lot of the problem

Since the Impeller is barely undersized and I can fix the blades up, the seals and bearing are all good on the unit and look like they have been replaced recently it should be fine to just get an undersized wear ring to fit my impeller shouldn't it? The .010 undersized would make the clearance .022 which would be right in spec. Do you want to hang around .024 clearance or do you want to go a little tighter? I would like to get this thing ordered today so I can get this boat back in the water. Thanks

Are there shims on the shaft? I think you need to check the clearance on the front face of the impeller and the wear ring shoulder also.

There were no shims at all on the shaft. I was debating on getting a new impeller also since yes this one does look a little old. Which I might as well get the Berkeley rebuild kit since its about $470 bux with impeller and the impeller alone is $330 plus $150 wear ring. I would imagine once I get it all tightened up it should act like a whole new boat.

Originally Posted by 84lsvette

There were no shims at all on the shaft. I was debating on getting a new impeller also since yes this one does look a little old. Which I might as well get the Berkeley rebuild kit since its about $470 bux with impeller and the impeller alone is $330 plus $150 wear ring. I would imagine once I get it all tightened up it should act like a whole new boat.

I wasn't sure about the shims, but the picture on post #4 where you are showing the wear ring. it looks like there was something on the shaft. it might just be my old blurry eyes.

It might have that 1 small shim on it still on the shaft. I didn't take anything else off of the shaft except the impeller. I have been trying to get ahold of tom at Jet boat performance but he is a pretty busy guy.

Talked to tom at performance jet and he's got me all squared away! Hopefully it wakes this baby up as much as I think its going to!