planing to buy 4 stroke 25 or 30hp

[cdy55]

I'am looking to buy a 4stroke,i have a 25hp mariner 2cycle(tiller) on my 15ft boat that i fixed up for fishing it was an 1966 runabout with an old 75 johnson remote on it i replaced it with the 25hp mariner it run 25mph with 1 person and 2 people 24mph with 3 ap.560# 23mph,my question is will a 30hp motor make any difference on speed,there is no hp rating on my boat ,i was thinking of putting a 40hp motor on but i'am afraid it might be to much motor for my boat.

 

[Jacques321]

Re: planing to buy 4 stroke 25 or 30hp

40 HP would be the absolute maximum HP I would clamp on the transom, and to be safer I would limit my choice to a 30HP 4 stroke.<br />Good luck with your choice of engine.<br /><br />I recommend a Yamaha or Mercury in the 4 stroke but there are other good engines on the market.

 

[ghostrider]

Re: planing to buy 4 stroke 25 or 30hp

What year is your 2-stroke?? pre 1987 hp ratings were at the powerhead. 1987 and on are rated at the prop. check the weight of your current motor and the weight of the 4-stroke you are considering. 4-strokes are considerably heavier, quieter, cleaner, and more fuel efficient. I'm old school--i prefer old faithful 2-stroke. good luck with your choice and selection.

 

[cdy55]

Re: planing to buy 4 stroke 25 or 30hp

my motor is a 1996 purchased new in 1999 it weighs 114# i bought it used in 2001 great motor only reason i may get a 4stroke is for trolling there quieter and don't smoke as much as a 2cycle,and the only reason i would consider a 30hp over a 25 is i'am hoping to maintain around 25 to 28mph with 2 or 3 people and fully loaded for fishing,i would like to hear from some one that had a 25hp and put on a 30hp motor on there boat and if it made much differance.

 

[Jacques321]

Re: planing to buy 4 stroke 25 or 30hp

Clint,<br /><br />I can't say that I've gone from a 25 to a 30 HP, but I can say that going from a 25 HP on my old Starcraft 150 FM (15 footer) to 40 Hp Mariner Magnum made one hell of a difference. At cruising speeds the engine (4 cylinders) exhibited less strain and it pushed my top end speed up to around 35 MPH!<br /><br />I'd say going from a 25 to a 30 would make a minor difference in speed and performance, but going to a 40 would make a significant difference.

 

[DJ]

Re: planing to buy 4 stroke 25 or 30hp

clint,<br /><br />I do not think you will see much difference in a 25 to 30.<br /><br />Where you will see more difference is in going to a three or four cyl. engine as opposed to a two cylinder. The extra displacenment will get you on plane faster and keep you on plane at lower rpm's.<br /><br />Perhaps a 35?