Do I have the right Prop? 14x16

[2fast4u_evinrude]

I kinda took a small chunk off my prop, not too bad but I figured a spare would be good to have. My boat is a 1976 OMC 4 cylinder 2.5L sterndrive. The current prop I have on it is a 14x16. I was looking around and a guy told me that a 14x16 prop might be too much for that boat and 14x14 would be better for it. Could this be true?

 

[steelespike]

Re: Do I have the right Prop? 14x16

We need a lot more info.If you read the stickies at the top of the paghe and ythe helps at the prop store page it will help you undewrstand prop selection better.
Need;boat size/weight,present max rpm and speed. Also the max rpm rating.
Depending on the boat and your activities; imo your 16 would be for water sports.
and a healthy 2.5 might over rev.

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

Hmm not sure of the weight of my boat, it holds 4 passengers, 16feet long. Heres a pic of my boat if that helps? Full throttle I rev at 5000rpm. In the mean time ill read the sticky

 

[steelespike]

Re: Do I have the right Prop? 14x16

I believe the 2.5 is rated at 4,600, ratio 1.72 so your not likely to be able to turn to much prop. If your tach is accurate you need to increase pitch. A 18" should put you at "about" 4,600.
How is your hole shot,do you know the max speed?I would guess max speed at around 40.

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

Read the sticky and im confused lol. Not sure what all those numbers mean. So what you are saying is that I should go with 14x18? I just want whats best for my boat and not putting alot of stress on it. We did pull a two person tube with the 14x16 prop on the weekend and it worked out great. I also found this link. So if I am reading it propperly I should have a 14x18 prop? 16feet boat 33-39mph

http://hhscott.com/evinrude/prop_chart_I4_120.htm

 

[steelespike]

Re: Do I have the right Prop? 14x16

Your rpm is a little high increasing pitch decreases rpm thus the feeling a 18 would put you at 4600 a reduction of "about" 200 rpm per inch increase in pitch.This would likely result in a slight increase in speed.
For water sports the 16 may be better ( more power) just watch the rpm.
Selecting a single prop for everthing is like picking a single gear in a car for everything there are comprimises.

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

ok so what you are saying is keep the RPM at 4600 max and I should be alright then? What I can do is for days that I pull a tube I can have the 14x16 on and days we just cruise around have 14x18 prop on. How would a 14x18 do when pulling a 2 person tube?

 

[SRC8778]

Re: Do I have the right Prop? 14x16

I have a 17' SeaRay with the same engine and outdrive. Right now it has a 17 on it which works out great for cruising around or fishing. When I bought it, it had a 15 on it which does a lot better for pulling but revs out a bit much and you have to watch the tach. I would say keep the current prop for pulling with and get a higher pitch for just cruising.

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

Ok cool, think I made my decision. I will keep the 14x16 on for tubing and buy a 14x18 for cruising.

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

I was also thinking of getting a 14x14 prop just to try it out. Do you guys think that would be worth while? I was told it would be good for cruising and keep the rpm down at 4000. Might be a gas saver

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

bump

 

[SRC8778]

Re: Do I have the right Prop? 14x16

A 14 pitch would be like a granny gear.

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

Ok, ill just stick with the 14x18

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

Just got the 14x18 prop in the mail on friday. Took the boat on the lake today it works good. I didnt noticed a difference between the 14x16 and the 14x18. When wide open throttle both rev at 5000rpm. I just cruised around all day and kept the rpm at 4000rpm. What other sizes can I try?

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

Anyone?

Anything else to maybe even make it faster.

 

[SRC8778]

Re: Do I have the right Prop? 14x16

As long as your motor will pull it, you can keep trying props with more pitch, 19,20,21,22,23... The higher the number, the farther the prop moves through the water with each rotation.

 

[steelespike]

Re: Do I have the right Prop? 14x16

If the 18 gives you 5,000 then a 20 would put you at "about" 4,600.With an addition of some speed.and a little less hole shot.Without speed figures your rpm doesn't mean much except you appear to be within specs. If your comfortable cruising at 4,000 thats fine but the most efficient speed could be anywhere from just on plane to about 600 to 800 more rpm.A 4 blade should get on plane easier,saving fuel,stay on plane with less throttle and diddling,saving fuel, plus handle better on plane and at the dock.Top speed will likely be less.

 

[2fast4u_evinrude]

Re: Do I have the right Prop? 14x16

So as of right now I have two 14x16 and one 14x18. THe one 14x16 has a chunk missing in it and I just took it into the shop to get repaired. The guy told me that he can change the pitch for me. Would this be safe to do? I was thinking of changing it to 14x20

 

[steelespike]

Re: Do I have the right Prop? 14x16

You might be able to do the 18 to a 20 but the 16 would be a stretch.
Any repitch is going to end up somewhat of a comprimise.
There a nice test report on the new Amita3 just posted here by walleyehed.