hello everyone

rainman55343 · 07-17-2013, 09:06 PM

Hey everyone. Have a question not happy with the performance with new motor. Have a 5.7 250 horse got in the 50's and 4800 for rpm with 19p 4 blade ss prop.problem is I want to go faster I want to go 60 or better. I want to race and beat my uncles boat. I'm thinking of going to a edelbrock intake and 4 barrel carb.I got a 2 barrel factory carb now. Any ideas everyone thx.

rainman55343 · 07-17-2013, 09:11 PM

Forgot to mention that's with a full tank of fuel and 2 adults and 2 kids.

Andy b · 07-17-2013, 09:38 PM

What boat has your uncle got?

***mikeyt*** · 07-17-2013, 10:09 PM

I seem to remember saying this once earlier: "I read somewhere a while back that for a 1 mph top speed increase you need at least 10 additional hp (all else being equal). I dont see your boat ever hitting 60 mph in its present form. And forget 60 mph on your speedo. Check it with a GPS." And now it appears that i wuz right.... To get that boat over the 60 mph mark you will have to do a number of improvements and they wont be cheap. Since your interest appears to be simply 'speed' it might be time to consider unloading your Mariah and buying a boat designed just for that purpose. The Mariah just isn't a 'speed' boat.

rainman55343 · 07-17-2013, 10:18 PM

He has a 19 foot tracker fiberglass with a mercury 150 horse outboard. His boat will do 65 mph.

Hey Mikey will keep the boat I have the 5.7 thought it would be faster In a 19 foot boat. How fast does our 4.3 do? I think an upgrade with intake and carb would Be a big difference with mine. Your 4.3

Hey Mikey u have any experience with performance spark plugs. I have boat them for cars in past but haven't noticed much difference.

I just a little more speed that's all. I have seen similar boats like mine with same setup go faster. saw a marada 21 foot with same setup go 60.

Andy b · 07-17-2013, 11:18 PM

I think the point you're missing and the point Mikey is trying to make rainman is there comes a point when a hull design reaches its peak performance,
And no amount of power is going to make it go faster! just it will become more and more unstable!!
Unlike cars that have to deal with aerodynamics at speed, Boat hulls have to deal with fluid dynamics.
The harder you push a boat through water the greater the Pressure wave and resistance to the boat becomes. And this resistance isn't a straight line

Too demonstrate my point it's the difference between putting your hand in water and then slapping the water. the resistance too your hand is far greater at speed
Mariah hulls offer superb all round performance but they are not race boats!

rainman55343 · 07-17-2013, 11:42 PM

I got mikeys point. Just disapointed with new motor. It cost me 3800 dollars. Would a edelbrock carb and intake help some. It would be about 600 dollars for that setup.

***mikeyt*** · 07-18-2013, 12:43 AM

Quote:

Originally Posted by rainman55343

He has a 19 foot tracker fiberglass with a mercury 150 horse outboard. His boat will do 65 mph.

Have u seen the hull design on a Tracker? Its not designed to cruise like a Mariah. Its designed to get fisherman to their spots very quickly and be stable at rest.

Quote:

Originally Posted by rainman55343

Hey Mikey will keep the boat I have the 5.7 thought it would be faster In a 19 foot boat. How fast does our 4.3 do? I think an upgrade with intake and carb would Be a big difference with mine. Your 4.3

Does it matter how fast 'our' 4.3 is? Yes, upgrading the intake/carb and numerous other things will improve the performance of your boat. You could also change out the pistons and the cam, increase your compression, install a turbo charger or a supercharger blah blah blah. But dont you think that Mercruiser or Volvo would have done so (or offered the options to do so) if it didn't affect the reliability of their engines? Spending a sh1tload just to gain 3 or 4 mph is a complete waste of money. The investment is just not worth the return when trying to make a boat faster than it was designed to be. Buy a boat that is designed to go faster if thats what you want.

Quote:

Originally Posted by rainman55343

Hey Mikey u have any experience with performance spark plugs. I have boat them for cars in past but haven't noticed much difference.

I've used them in vehicles and saw no performance (speed) gain. I did find that my cars started easier in the winter and i think the plugs lasted longer. But then i dont boat in the winter.

Quote:

Originally Posted by rainman55343

I just a little more speed that's all. I have seen similar boats like mine with same setup go faster. saw a marada 21 foot with same setup go 60.

You must have been looking at the speedo.... next time use a GPS.

rainman55343 · 07-18-2013, 12:51 AM

I will GPS soon. And try 3 blade aluminum prop. Might just do carb and intake and be done. Won't do any more after that. If I go from a 2 barrel merc carb to a 4 barrel edelbrock is it going to use a lot more fuel or less fuel.

I will never buy Bosch plugs again. Bought 2 sets for cars in the past and both sets didn't last long and didn't do anything.

***mikeyt*** · 07-18-2013, 01:16 AM

Quote:

Originally Posted by rainman55343

I will GPS soon. And try 3 blade aluminum prop. Might just do carb and intake and be done. Won't do any more after that. If I go from a 2 barrel merc carb to a 4 barrel edelbrock is it going to use a lot more fuel or less fuel.

More fuel. Ever play in a water puddle as a kid? What happens when you make the drain from your puddle larger?

Quote:

Originally Posted by rainman55343

I will never buy Bosch plugs again. Bought 2 sets for cars in the past and both sets didn't last long and didn't do anything.

Then you have answered your own question.