New prop help pulling a skier?

[WhereBob]

I am looking at a boat with a 3.0L 140 hp mercruiser inboard and I want it to be able to pull me (175lbs) sking slalom. The owner (220lbs) says it doesn't have enough pop to get him up slalom. I like the boat but want to be able to ski slalom.

My question is will changing props give the boat more pop? It has the stock prop on it now.

Thanks

 

[Silvertip]

Re: New prop help pulling a skier?

Determine what the pitch of the current prop is and buy one (new or used) that has 2 inches less pitch. That will provide the hole shot you need for skiing. Because lowering pitch is like shifting down a gear in a car, you will need to watch the tach to avoid over reving the engine. Keep the existing prop for cruising. But before spending money on props, make sure the engine is in proper state of tune and making full power and that the boat isn't full of water soaked foam.

 

[WhereBob]

Re: New prop help pulling a skier?

Thanks for the reply.

Right now I am just looking at buying the boat and sking with it is in the future. I really just need to know if changing props will give me the torque I may need or if I should just be looking for a boat with a bigger motor such as a 4.3L

 

[MikDee]

Re: New prop help pulling a skier?

You decide what motor you want, but a 4blade prop 2" less pitch then whats on there (if it has the recommended one?), will do wonders for torque on either motor, but scrub just a couple, or a few mph, but no big deal.

 

[ekinnee]

Re: New prop help pulling a skier?

I posted this in reply to the question in the Mercruiser section:

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.

 

[Silvertip]

Re: New prop help pulling a skier?

Actually a boat motor is not as different from a car as you might expect. In fact it is very close to the same cam profile as in a truck (although the 2.5 and 3.0 were never considered truck motors and 3.0 was never used in a car). Just because you can make a motor rev higher does not make it a good motor for a boat. All you end up doing is moving torque and HP higher in the rpm band. That does you absolutely no good when you are trying to get out of the hole.