more speed

[castn and blastn]

i have a 19 foot 2001 duracraft and a 91 evinrude 140 looper cross flow witch is like new and has 21 comp cylinder and has a 13x21 raptor prop and a big fin and on gps i only do about 43 not that i need to go faster but dont you thank i should go faster

 

[NelsonQ]

Re: more speed

What RPMs are you turning at WOT?

On a 19' boat with a 140HP engine, I'm not sure if you could expect much more than another mile or two per hour in speed.

 

[Bob_VT]

Re: more speed

Welcome to iboats.

Ahhh this is a prop question so I will move it for you.

What RPM's are you at WOT?

Where is the engine mounted in relation to the hull....... the ventilation plate ..... below the hull or above?

Yes I agree you should be seeing a bit more speed.

 

[Dhadley]

Re: more speed

So.....is it a 140 crossflow or a 140 looper???

 

[castn and blastn]

Re: more speed

it a looper and i thank what u mean by ventilation plat is what u mount the fin on it flush with the bottom of the boat and at wot im running between 5200 and 5300 when i had my old prop it was 5500 but i got the same speed but i did add a fin when i got that new prop . and keep in mind this is a aluminum cc a light boat i just thank it should fly

thank u

 

[steelespike]

Re: more speed

The fin will lose some speed.And weight is only part of the speed equation.
In my experience speed varies widely over al.boats of similar styles. both speed and prop selection vary widely.Generally a heavier fiberglass boat will run faster than a similar lighter aluminum boat.Some aluminum boats disturb the water so much they can cause high slip numbers.
You should raise your motor to a point just before venting becomes a problem.
You should be able to see the antivent plate easily on plane.
Be sure the throttle plates open all the way.Bottom clean and smooth.

 

[junior1113]

Re: more speed

fins suck, they put more stress on motor mounts and transom as well as hrd turning . id pul fin off and raise motor up or get manual jack plate to achieve optimal height. i had a 93' 140 with a vented turbo ss 21" prop on 18 fourwinns it did 46mph@ 5550rpms. great motors. remember its only a four banger.

 

[castn and blastn]

Re: more speed

thank you, Ill take the fin off and see what she will do .I herd by puting a jack plate on will stress the transom and will break it after time, and if any body could tell me step by step how to tune my engine and check the timing

thank u