New propellor size good idea or not?

[rustyoletoy]

I have a 1991 25hp that I want to change the propellor on because one of the blades is damaged. Currently it runs a 11 x 13 3-blade prop.<br /> The boat that the engine sits on is 14' long and weighs around 200lbs. (inflatable) Usually it carries 2 or 3 adults when we go out for the day. Should I stay with the same size prop? It seems to work ok but if I can get better performance, I may as well do it now! <br /> I was thinking about one of those composite blade props (like ProPulse) with variable pitch because that seems like it would let me test to find what works best for me. <br /> Usually I use the boat to go from point A to point B and explore but sometimes I want to pull stuff or fish or stuff so a do-everything prop is what I want. <br /> Also everything that I read says you should keep the engine between certain RPMs. How do I figure that out on my engine? I have a dwell/tach meter that I used to use for tune-ups on an old car I had, can I hook that up temporarily and if so where?<br /><br /> Sean

 

[gasguzzler]

Re: New propellor size good idea or not?

I have a write up thats intitled "proper proping".It is very good and explains the details clearly.I highly suggest reading it. Contact me at thunderjet429460@aol.com if you would like a copy.

 

[Hooty]

Re: New propellor size good idea or not?

Your tach/dwell meter ain't gonna do it. Call TinyTach, tell 'em what engine you've got and for about forty skins, they'll send ya a tach. It's worth tha money and you really need one to prop your boat with.<br /><br />Here's their website:<br /> TinyTach <br /><br />c/6<br />Hooty

 

[cobra 3.0]

Re: New propellor size good idea or not?

Ditto to the above. You may end up finding out that a 15" pitch may give you a little more top end on light loads, but will not give you the same torque/power to handle three people and/or tow stuff as well as your 13" pitch.