Mods to a 3.0 140 hp mercruiser to pull a skier?

WhereBob

Petty Officer 3rd Class
Joined
Apr 29, 2004
Messages
82
What can I do to a 3.0 140 hp mercruiser inboard to get more power or torque to lift a slalom skier out of the water?

Thanks
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Mods to a 3.0 140 hp mercruiser to pull a skier?

Either a bigger engine, or under-prop it so you get more low end, but less top end speed.
The prop forum would be the best place to post your prop size question.
 

ekinnee

Seaman
Joined
Jul 24, 2008
Messages
62
Re: Mods to a 3.0 140 hp mercruiser to pull a skier?

My 18' works just fine for pulling folks up and out of the water, I run a 14.5x19 Solas Rubex prop.

The performance upgrade thought I too got early on was soon shattered by the fact that there's nothing out there. Nothing short of a cam, port / polish the heads, over bore the cylinders. At that point, you're looking at spending more than it's worth for the meager gains you would get out of our little 4 bangers.

One of the big errors we make is thinking in terms of a car, the power band in a boat is totally different. From what I see it's much flatter in a boat than a car and a boat motor is meant to be run wide open if you want to go fast. Forget torque figures and realize it's all about how many horses you can crank out. For us, it's pretty much 140 and that's it.
 

KJSmitty

Petty Officer 2nd Class
Joined
Aug 9, 2008
Messages
179
Re: Mods to a 3.0 140 hp mercruiser to pull a skier?

^^^^^Don't forget however,

In a boat, just like a vehicle - "torque" is what gets you moving. HP determines how fast that movement will be....

:D
 
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