More speed!

[Chrisford4x4]

I am looking to get alittle more top speed out of my boat. I have a 1985 Starcraft SS 160 with same vintage 50 hp Johnson.
I can get it up to 30mph with two people on calm water using a 12-1/4x 15 (stock) aluminum prop. I would like to bump up the top speed alittle because i'm a guy and I like to go fast. I don't have a tach but boat will go from 0-30mph very quick and would be willing to sacriphise a little to gain some more up top. Does anyone have any input on how i might do this?

 

[torbjorn]

Re: More speed!

I am looking to get alittle more top speed out of my boat. I have a 1985 Starcraft SS 160 with same vintage 50 hp Johnson.
I can get it up to 30mph with two people on calm water using a 12-1/4x 15 (stock) aluminum prop. I would like to bump up the top speed alittle because i'm a guy and I like to go fast. I don't have a tach but boat will go from 0-30mph very quick and would be willing to sacriphise a little to gain some more up top. Does anyone have any input on how i might do this?

First, how many RPM are you turning? Second, jack the motor up to 17 5/8-18" if shortshaft, add 5" if longshaft. That's the first thing to do to reduce gearcase drag. You can buy an OMC SST prop, better is a Stiletto. The motor should be turning upwards of 6000 RPM with the right pitch prop, so you need to get a tach and check it before going further.

 

[steelespike]

Re: More speed!

Please read "read this first" at the top of the page. A tach is a must when making any prop/setup change.
The motor developes its power at 5000 rpm suggested rpm range is 4500 to 5500. I sure wouldn't be running it at 6000+
without the Evinruide dealer says no problem. The farther you get from the rating the less power developed.
Is your speed by gps?
Aluminum boats generally are slightly slower than a fiberglass boat if similar style but heavier weight.
Is the antivent plate(just above the prop) about even with the bottom of the transom?

 

[sutor623]

Re: More speed!

I am looking to get alittle more top speed out of my boat. I have a 1985 Starcraft SS 160 with same vintage 50 hp Johnson.
I can get it up to 30mph with two people on calm water using a 12-1/4x 15 (stock) aluminum prop. I would like to bump up the top speed alittle because i'm a guy and I like to go fast. I don't have a tach but boat will go from 0-30mph very quick and would be willing to sacriphise a little to gain some more up top. Does anyone have any input on how i might do this?

I have an '86 Starcraft FM, which is the same boat, minus one of the side consoles. I have a 65hp on it and am pushing around 35. Id say you are more than likely getting as much as you can out of that 50hp motor. What is the rated HP on the transom? Mine is 90.