how fast should my 140 inboard go ?

[Rienel]

I have a 140 merc cruser on an 17' Glastron modified trihull with a 17" prop and im wondering what kind of speed i should get. Im thinking of going to a 21" prop but don't know how that would work out.<br /> Tks

 

[moderator1]

Re: how fast should my 140 inboard go ?

Moving to I/O's.

 

[Juancho]

Re: how fast should my 140 inboard go ?

I'm not sure, putting a larger diameter prop on there is going to increase your speed. However, putting a higher pitch prop on there definately would. I have a 19 ft Bayliner Capri, and the ideal prop for that boat is a 14.25" X 19 pitch. I would imagine that with your boat it would be somewhere around there. Maybe 15 X 21? You have more horsepower than me, so you can turn a bigger screw.

 

[MrDumb]

Re: how fast should my 140 inboard go ?

Just a thought you might drop off to many rpms? Going with that big of change in pitch. On my boat I have a 15x17 prop and it runs about 37mph @ WOT. It is rated at 135hp.

 

[akriverrat]

Re: how fast should my 140 inboard go ?

without knowing the present wot with the prop you now have none of this is more than a wild ass guess. you might be carrying a volkswagon around with you or a passanger that weighs as much as one.

 

[Bondo]

Re: how fast should my 140 inboard go ?

Yep, It's the RPMs, Not the MPH......<br /><br />I Wish it was that Easy to go Faster....

 

[Gunny77]

Re: how fast should my 140 inboard go ?

I have a 2003 Stingray 180LS with a 3.0 135 hp Volvo. <br /><br />14.25 x 19" aluminum @ 5000 rpm WOT 44 mph<br />14.50 x 21" aluminum @ 4900 rpm WOT 46 mph<br /><br />This with 3/4 fuel and 3 adults<br /><br />Maunfacturer rates this boat @ 49 mph with a 23" prop under "ideal" conditions.

 

[Crazy]

Re: how fast should my 140 inboard go ?

I had a little 16.5 foot 120hp merc I/O . with me 230lbs and my freind 270lbs and a full tank of fuel 20 gal , it would do 37.2mph on GPS at 4200 rpm .