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Correct Propeller - Yamaha 115 2 Stroke

H

Hofty

New member
Hey folks,

I have a 17ft fibreglass ski boat. Currently I have a 13x21K propeller which is a little old and has seen its days. It runs great and get me out of the hole with no problem. I am WOT 4900RPM with 2-3 people. The local boat shop has a second hand great condition stainless steel 13X17 propeller with 15 tooth spline and they are offering it for $100 depending on who I speak too.

Would I benefit by using this lower pitch propeller? I usually cruise around 3500-3800RPM comfortably with the 13X21 but hoping that the 13X17 stainless might be a good deal (Better fuel economy at cruise speed?) and soon I will be hauling some friends on a tube also taking 4-6 big guys on the open ocean. Any advice in this regard? Buy the 13x17 or save my $ for a 13X19 aluminium ?
 
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I would give it a try. You are over propped right now. However, going down four inches of pitch might be a bit much. You can only tell by installing and testing the propeller. See if they will loan it to you for a while. Load the boat and then run it at wide open throttle. Motor only trimmed up to the point of best efficiency and no further. Ideally you want the motor to be turning at or near its red line RPM of 5500.
 
Well that sort of seems to answer the question. Wondering if they will loan the prop with a deposit to see if it works out. Yeah I still think the 19 prop is the best route to go but 17 SS might work out in the end. Only a test run will tell. Ok tomorrow I will go see if it’s still available and give it a whirl.
 
Dunno your model year....but most likely spec rpm range at WOT is 4500-5500. As boscoe stated, your over propped w/21". But the 17" will prob put you out of range. I have a 17' fiber cc w/'98 115hp. I also had a 21" overprop issue. Trialed a 17"...high 5k. Then trialed 18" merc ss that put me right at top end rpm range.
 
ClassicAQ said:
Dunno your model year....but most likely spec rpm range at WOT is 4500-5500. As boscoe stated, your over propped w/21". But the 17" will prob put you out of range. I have a 17' fiber cc w/'98 115hp. I also had a 21" overprop issue. Trialed a 17"...high 5k. Then trialed 18" merc ss that put me right at top end rpm range.
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Thanks. I have tried the 17 and it’s seems decent for cruising. The 21 was overkill but now the 17 seems decent.
 
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