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Prop and Motor question from a new guy

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ngaraiderman

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I've got a new to me 2005 Benny 2275LX with Johnson 90hp 4 stroke motor. my current prop is 3x14x17 aluminum. Im not sure of the make, it was on the boat when I bought it. At WOT im getting between 21-22 mph on my GPS @5000 rpm's.  I looked up the specs on my engine at its says the RPM range is 4500-5500. The motor is on the second from the top hole on the transom. Does this sound correct? I'm just looking to get the best out of what I have and If I need a new prop what is recommended.


we usually have 2-4 adults and 2 kids onboard and pull several inflatables.


Thanks for any info you guys can give to a newbie.


Jeremy
 
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Welcome to the family. Are you sure that is an 8 and not a 3 on the prop numbers? 14x17 is too much prop for that combo of boat and motor size. You should have at least a 15 if not a 13 pitch prop on it. I have a 15 pitch on a 150.
 
Yes sir you are correct with the 3. I must have fat fingered it. So do I need the same diameter? A 14" with a 15 pitch or a 15" with a 15 pitch? 
 
I am thinking a 13 pitch. Is there someone that is letting you try these props until you find the correct one? Do you have a 2 or 3 tube boat and do you have strakes?
 
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If you are buying all these props, you should try ebay. I bought on ebay and sold what I didn't use on ebay. It kept the cost down.
 
I found this PROP.
 
Thanks. I just ordered that one. Hopefully I can give it a try next week when it comes in. Im also going to fabricate and install some wave shields like HAPEHOUR did. I attached a photo of my motor setup. Does this look correct?


thanks for the information.


Jeremy

motor1.png
 
The only way to check motor height is while you're cruising and looking at the cavitation plate. It should be at or just below the surface of the water.
 
cwag911 I got a new prop. Its a 13.75x13. it brought my RPM's up to 6000 but my speed went down to 18-19 mph on my GPS, but it seems to have given me better pulling in turning and trying to sling shot the towables and wake boarders around. I was a little disappointed so I just ordered a 13.75x15 Solas Amita 4 blade to try out this week sometime and im assuming it will lower my RPM's a little but hopefully I will gain that back if I raise the motor some.. I still think the motor is still to low, so I may try to raise a notch or two. This is WOT at 6000 RPM's and 18-19 Mph on GPS and it trimmed up as high as it will go with out slipping or blowing out


Thanks guys


cavitation plate 1.jpg
 
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ngaraiderman said:
cwag911 I got a new prop. Its a 13.75x13. it brought my RPM's up to 6000 but my speed went down to 18-19 mph on my GPS, but it seems to have given me better pulling in turning and trying to sling shot the towables and wake boarders around. I was a little disappointed so I just ordered a 13.75x15 Solas Amita 4 blade to try out this week sometime and im assuming it will lower my RPM's a little but hopefully I will gain that back if I raise the motor some.. I still think the motor is still to low, so I may try to raise a notch or two. This is WOT at 6000 RPM's and 18-19 Mph on GPS and it trimmed up as high as it will go with out slipping or blowing out


Thanks guys


View attachment 1757
Click to expand...

It looks like you could raise it up a notch.
 
ngaraiderman said:
cwag911 I got a new prop. Its a 13.75x13. it brought my RPM's up to 6000 but my speed went down to 18-19 mph on my GPS, but it seems to have given me better pulling in turning and trying to sling shot the towables and wake boarders around. I was a little disappointed so I just ordered a 13.75x15 Solas Amita 4 blade to try out this week sometime and im assuming it will lower my RPM's a little but hopefully I will gain that back if I raise the motor some.. I still think the motor is still to low, so I may try to raise a notch or two. This is WOT at 6000 RPM's and 18-19 Mph on GPS and it trimmed up as high as it will go with out slipping or blowing out


Thanks guys


View attachment 1757
Click to expand...

2nd on the raise it up one hole. Remember to just do one thing at a time and record the data, too many things at once and you'll have no idea good or bad what works. Good luck!
 
Real curious to see what kind of numbers you get with the 15 pitch 4 blade. Keep us posted. 
 
I have had two bennington's had both of them on the highest hole the higher you go the faster you go if you have big power 150 plus you should have a Jack plate. 
 
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