new carbs maxum 3300

Hello All

I have a 2001 maxum 3300scr with twin 5.7l mercruisers and Bravo 2 drives.
Its proped with 19 pitch,19 inch SS props.
These are 250 hp engines with 2 barrel carbs.
My hole shot is about 5 seconds.
Im thinking about changing out my intakes and carbs to 4 barrel and going up to 21 pitch props.
My thought is with the increased HP (about 15 per side} my hole shot with 21 pitch should be the same.
The endgame here is to save fuel by keeping my secondaries closed while cruising at my sweet spot.
Theoretically my sweet spot shout be a couple of MPH faster.
My question is what would be the best 4 barrel carbs to use to accomplish this.
Also would a 4 blade prop SS have a positive effect?

Eric
owner of Layinawake

Re: new carbs maxum 3300

On the down side:
A total of 30 HP is not going make the difference you are looking for, I'm sorry to say. That 30 (total) hp is going to be at the top of the RPM range, if at all. And you wont know for sure without putting them (motors) on a dyno.

Changing from 19 to 21p props is only going to make the hole shot worse also, and you probably will lose top speed.
What your looking for is torque. A 2 bbl has more, and at a lower rpm than a 4 bbl has.

On the up side:
a 4 bbl usually gets better mileage because you can stay out of the secondaries, and the primaries are smaller than a 2 bbl.

Increasing each engine to around 300 hp would be a better solution, and give you more top speed also. But again you will use more gas.

I don't mean to sound like an *****, but in boating there is a saying, "if you want a faster boat, you buy a faster boat."
95% of all boats come from the factory about as good as they are going to get.
Bass boats are the only exception I'm aware of. And then you have to get the top of the line ones so you don't go over the recommended HP.