50 hp Mariner, 28mph max , how can I get it faster?

[Karl Seibel]

Have a 1990 50 hp Mariner on a 1988 Pro-Craft Bass boat. How can I get the speed a little higher? Different prop? And how much more speed will I get with a different prop. Got just about the original prop on it as of now. Is that about the right speed for a 50hp on this boat? Not sure how much the boat weighs.

 

[Hooty]

Re: 50 hp Mariner, 28mph max , how can I get it faster?

How many revs is the engine turning?<br /><br />c/6<br /><br />Hooty

 

[Karl Seibel]

Re: 50 hp Mariner, 28mph max , how can I get it faster?

Hooty, I'm new at this game...how do i check that...sorry to sound dumb ...but when it comes to engines ..just don't know how to check things...thanks Seibel

 

[Hooty]

Re: 50 hp Mariner, 28mph max , how can I get it faster?

Hey Seibel,<br /><br />No problem. I guess that means you don't have a tachometer. That's the instrument that reads engine speed in revolutions per minute (rpm). When proping a boat and engine, it's necessary to have one. The engine has a maximum speed, measured in rpm, where it developes it's maximum horsepower. Usually between 5500 and 6000 rpm. You want a prop that will allow the engine to turn this speed and no more. <br />Use your browser and find "Tiny Tach". They're inexpensive and easy to install. Then we can prop your boat.<br /><br />c/6<br /><br />Hooty

 

[andrewkafp]

Re: 50 hp Mariner, 28mph max , how can I get it faster?

What would you expect a 1985 Merc 50 (4 cyl) to peak at in knots ?<br />This is on a 4.5M half cab with 2 on board and full tanks .<br />I've had it to 4000 rpm, but forgot to look at speedo !!!!

 

[horndog]

Re: 50 hp Mariner, 28mph max , how can I get it faster?

sounds like the motor is working pretty good. <br /><br />You never stated what kind of boat this motor is on, that makes quite a difference. Also how much stuff do you have in the boat, the more weight the slower it will go