Upgrading My Outboard Motor

[Majiklegs55]

I have a 1991 Boston Whaler Sport w/15hp Honda<br />electric motor. I am thinking of going up to a<br />Yamaha 25hp motor....Will I experience a significant increase in overall speed? Enough so I can go for rides in the Ocean on a calm day?

 

[JB]

Re: Upgrading My Outboard Motor

Ahoy, Majiklegs.<br /><br />Is your Whaler an 11' or a 13'? <br /><br />The 11' Sport is rated for 20hp and the 13'Sport for 40hp.<br /><br />I have a 9.9 Johnny 4 stroke on my 11' Tender (tiller steer), which is max. It will plane with one aboard, but not much more than that.<br /><br />I have had several 13' Sports and it is a much faster boat. Even with a 25 it is good for 25mph with 3 aboard. I have used bigger engines but they make it stern heavy and it doesn't handle as well, but it goes like stink. In my opinion, a 25 is ideal for the 13 Sport.<br /><br />If yours is an 11' Sport, go for a 20hp engine but don't expect that short, wide boat to be a water rocket. It won't be much faster than the 15.<br /><br />Happy boating.

 

[Selles]

Re: Upgrading My Outboard Motor

I have wailer 13ft 25hp Mariner short shaft move this boat too low ,propeller 3x10x11p, too many cavitation , help me , JB.

 

[Spidybot]

Re: Upgrading My Outboard Motor

Selles,<br /><br />If you want an answer to a specific question you should start your own, specific, topic.<br /><br />By throwing your own question in on somebody elses thread you have only a little chance of getting answers.<br /><br />And, please, be a little more explanatory. We can't read your mind, so tell us in plain words what we may help you with.

 

[Lark40]

Re: Upgrading My Outboard Motor

UU,<br /><br />You are right that Selles should have asked his question in a separate thread.<br /><br />But, I think his issue is poor performance due to cavitation. Which is really two questions:<br /><br />1) Is the the short shaft engine correct for that 13' Whaler?<br /><br />2) Is the 11" pitch prop correct for that rig?

 

[Spidybot]

Re: Upgrading My Outboard Motor

Yes, Lark, I think you're right about the core of the problem.<br /><br />That emphasizes the need for it's own thread and also tempts one to suggest a search on these forum's ...<br /><br />More, much more, info is needed to give good advice. Boat weight and load, motor mount, trim angle, prop condition, motor tuning... to name a few.