13.75 x 21 VS. 14.25 x 23???

[brsox88]

The 21 pitch prop is what I had on my boat, and I have gone with the 23 now. Whats the difference between the two? Higher speeds or better acceleration?

This is going on a 1996 Searay 175 3.0 135hp boat.

 

[90stingray]

Re: 13.75 x 21 VS. 14.25 x 23???

Generally, talking similar props... I.e...both being 3 blade aluminium...usually the lower the number the better the holeshot. but there are lots of other factors that can play in if you go stainless or go more blades, different degrees of rake... You see where this is going. But the 23p should give you more top speed. Where is your rpm now? What are you trying to achieve?

 

[Bamaman1]

Re: 13.75 x 21 VS. 14.25 x 23???

Are you getting the specified redline with a 23 pitch prop? If so, that's impressive. That engine usually is best with 19's and 21's.

 

[Robbabob]

Re: 13.75 x 21 VS. 14.25 x 23???

The 23 will give you more speed only if you have the available HP and room for the rpm drop. Likely, if you weren't too high in rpm before, your hole-shot will take longer and your top speed will go down (lugging the engine).

 

[brsox88]

Re: 13.75 x 21 VS. 14.25 x 23???

The 23 will give you more speed only if you have the available HP and room for the rpm drop. Likely, if you weren't too high in rpm before, your hole-shot will take longer and your top speed will go down (lugging the engine).

Well I dont know if it was red lining. I bought the boat in the winter and the previous owner dug up the prop so I had to replace it and months ago people on here recommended the 23 that I ended up buying. Is it bad for the engine to be lugging at WOT and possibly consider selling this prop for a 21 pitch?

 

[mr 88]

Re: 13.75 x 21 VS. 14.25 x 23???

The engine should be close to the recommended rpm's at WOT.They usually give you a 400rpm variance. So if they say 42-4600 and you have your normal load, then 41-4700 is where you should be.Most opt for a higher pitch that would put you at the low end of the rpm scale,4-4200.If you are waterskiing etc then you go with a smaller pitch which give you a better hole shot,but you lose some top end and fuel milage. Lugging a motor is like trailering your boat uphill,non stop.The motor takes a beating and fuel milage decreases. If "people on here " rec. a 23" is it because they had the exact same setup as you? IT sounds to me like you are way over pitched. I agree with the one post that 19" seems more correct for that setup.Putting a 23 on will not give you more speed unless you are running in the correct RPM zone,period.A 19"X 4600 rpm =87,400 or 7283 feet, now take a 23"x 3500rpm=80,500" or 6708 feet ,which amounts to 575 less feet in the same minute of time or almost 2 football fields.

 

[brsox88]

Re: 13.75 x 21 VS. 14.25 x 23???

The engine should be close to the recommended rpm's at WOT.They usually give you a 400rpm variance. So if they say 42-4600 and you have your normal load, then 41-4700 is where you should be.Most opt for a higher pitch that would put you at the low end of the rpm scale,4-4200.If you are waterskiing etc then you go with a smaller pitch which give you a better hole shot,but you lose some top end and fuel milage. Lugging a motor is like trailering your boat uphill,non stop.The motor takes a beating and fuel milage decreases. If "people on here " rec. a 23" is it because they had the exact same setup as you? IT sounds to me like you are way over pitched. I agree with the one post that 19" seems more correct for that setup.Putting a 23 on will not give you more speed unless you are running in the correct RPM zone,period.A 19"X 4600 rpm =87,400 or 7283 feet, now take a 23"x 3500rpm=80,500" or 6708 feet ,which amounts to 575 less feet in the same minute of time or almost 2 football fields.

Hmm well I sure hope its not that bad, at 3500rpm but I guess I will find out soon.