Impellers

[Bruce]

Here are the details

The 2007 & 2008 230 manuals specify the all-HO SX/SR prop pitch as Port 16.3° / Starboard 17.3° and the all-HO AR prop pitch as Port 18.1° / Starboard 15.1°.

The 2009 230 manuals specify the prop pitch for both the SX, AR, Limited and Limited S as Port 18.1° / Starboard 15.1°.

More info in this thread https://jetboaters.net/threads/does...-mr1-versions-hp-and-impeller-questions.8478/

I am curious if the difference in our 46 MPH boats and Boattest's tested 50 MPH is that a different impeller was installed at the factory.

 

[Chillypilot]

@bronze_10 I don't know if this will help you determine if your impellers are on the correct side. Here is a picture or both of mine for comparison. The damaged impeller is the port side impeller.(6p600)

 

[bronze_10]

My speed o meter says 50 to 51 but GPS says 46 to 47... I can try to determine the part numbers if I can get to them.... I will most likely change the impellers this winter.

 

[bronze_10]

Where r the part number found? At the base of the impeller?

 

[Scottintexas]

from my 2007 HO mtc manual

 

[Chillypilot]

 

[bronze_10]

I Prob won't pull them out till winter..

 

[jcyamaharider]

Just replaced my impellers but not the housings. WOW what a difference in low end out of the hole, but of course that is what I had them pitched for. I did loose top end but only a couple of MPH. I still hit 46-47 MPH.

 

[Scottintexas]

@jcyamaharider did you have the stock impellers repitched or buy aftermarket ? do you know what they were pitched to ?

 

[jcyamaharider]

@jcyamaharider did you have the stock impellers repitched or buy aftermarket ? do you know what they were pitched to ?

I bought aftermarket Solas impellers and had impros repitch them. They didn't tell me what the pitch was, I think they like to keep that a secret.

 

[B. Carry]

Actually mine is quite a bit worse. Still worked fairly well. But there was some cavitation at certain power settings

View attachment 36659

I have a 06 ar210. Noticed the last couple yrs when pulling a 2-3 person tube there is a lot of cavitation. Pulled the impellers and they look great. Planning on changing them for better low end. Any recommendations?

 

[Chillypilot]

@B. Carry I purchased Solas impellers from Impros. They can pitch them however you like. I haven't had my boat in the water yet so a can't comment on how they work. However, since you said your stock impellers were in good condition I would look for the reason you're experiencing cavitation before I went out and purchased new ones. The usuall culprit is silicone missing aound the intake grate.

 

[swatski]

I have a 06 ar210. Noticed the last couple yrs when pulling a 2-3 person tube there is a lot of cavitation. Pulled the impellers and they look great. Planning on changing them for better low end. Any recommendations?

What @Chillypilot said - check the sealant around the pump shoe, wear ring and transom plate. Anything missing can cause major cavitation.

Also - check the impeller clearance with a feeler gauge. If you don't have one handy, if you can stick a knife blade between the edge of the prop blade and the wear ring its too much clearance (keep in mind the less clearance you have between the wear ring and the prop blade without them touching the more efficient your pump will perform).

.014-.020 thousands inch is the specification any more than .025 thousands inch max and you speed and acceleration will suffer real bad.

 

[swatski]

Actually, I just checked again, the clearance - I was off a bit:

 

[Chillypilot]

@swatski Interesting thing on the clearance, my starboard solace impeller has a significant amount of clearance. More than Yamaha states. I called David at Impros to make sure it was right and he said that was normal because of the the amount of re-pitch. The more you bend it the smaller it gets. Makes sense I guess. He said the performance gains with this impeller will far outweigh the loss caused by the increase clearance.

 

[swatski]

@swatski Interesting thing on the clearance, my starboard solace impeller has a significant amount of clearance. More than Yamaha states. I called David at Impros to make sure it was right and he said that was normal because of the the amount of re-pitch. The more you bend it the smaller it gets. Makes sense I guess. He said the performance gains with this impeller will far outweigh the loss caused by the increase clearance.

@Chillypilot Thank you for sharing, that is definitely good to know... I must say, I am a bit dumbfounded .

Impeller's OD (outside diameter) does change during repitch, it gets smaller or larger depending on which way you bend. Not all impeller models are equally susceptible depending on the blade root design, I believe Solas in general (and Solas Dynafly in particular) are more affected than Skat or OEM. So yes, it is "normal" for the clearance of a repitched impeller to be out of whack.

BUT...

That is also precisely why repitching is so tricky and not always economically feasible - if you go past a degree or two (again - depending on which impeller and edge) - you have to file down or weld back on material to restore the impeller's OD clearance, the latter being more difficult and pricey to fix. And that is also why most of us do not repitch our own impellers.

As far as performance gains - you might gain some top end speed; the smaller OD impeller will spin faster and will (eventually) push the boat to a higher top end speed. It will take a long time to get there, the conditions will have to be perfect and there will be a lot more prop slip on hole shot and along the way, but there will be (modest) gains of top speed. Unless you are on the rev limiter already.

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