Calling all prop guru's

[wcsellers]

Here's the delima...
I bought this boat last year and first time out I tore up the prop. Ordered the same as the one that was on it. It appears to be a 14 x 23p. So, knee boarding behind the boat I noticed alot more turbulence than behind previous boat that had a 19p. According to manufactures specs (http://www.wellcraft.com/owners/infoguides/1993/EXCEL_PIG_20SX_IO_Bowrid_93.jpg) I should be proped right. I can take her to 44.8 mph per gps at 4800 rpm, but this motor can turn to 5300 rpm with no noticeable increase in speed (not over trimmed)
What i am wondering is if I have it over proped and it is cavitating. The new prop has alot of wear for only 20 hrs, of use. I was thinking of going to a 21p. thanks for the advice

Spec: 1993 wellcraft excel 20 sx
volvo-penta 430B (4barrel 4.3)
volvo-penta SP-C outdrive with 1.89 ratio

 

[wcsellers]

Re: Calling all prop guru's

this is the part number on side of prop that I have
C854980

 

[usskydvr]

Re: Calling all prop guru's

That C854980 is indeed a 14x23. Your pic indicates cavitation. A 4.3 pushing a 20 ft boat with anything other than a VERY light load is too much for that 23. A 21 would be a better match and even a 19 if you have 3-4 folks, a full load of fuel and are pulling a skier.

 

[BF]

Re: Calling all prop guru's

Maybe unrelated.... but it looks like the skeg has been ground down as it's much shorter than the bottom of the prop. Is there any roughness/pertrusion to the skeg that might be contributing to the cavitation? BTW, if it were me, I'd take that to a good welder and have him rebuild the skeg so that it actually projects below the prop.

 

[wcsellers]

Re: Calling all prop guru's

That C854980 is indeed a 14x23. Your pic indicates cavitation. A 4.3 pushing a 20 ft boat with anything other than a VERY light load is too much for that 23. A 21 would be a better match and even a 19 if you have 3-4 folks, a full load of fuel and are pulling a skier.

Well, thought the same until I had it out a few times. 6 adults, full gas, and one knee boarder she pulls great but it isn't the average 4.3. According to volvo-penta she puts out 205 hp and it fells much stronger than other 4.3's I have driven.
As far as the skegg, I think that happend when I tore up the prop but its not bent.
How much will the top end suffer from a 21p prop? I guess if it has less slip it could actually stay the same or gain some speed?

 

[sethjon]

Re: Calling all prop guru's

21 would be much better.