think of it more this way
imagine the 5 series bmw, you can get a 1.8 version right up to a 4.4v8 and then the m5. you will get different performance from each engine version.
now with your boat, if is rated 50 hp max then you should be fine for performance. however if it is rated at 100hp and 50 is acceptable then the engine will be working harder and this is when the traits of a 2 stroke over 4 stroke will show
i always believe that going for the biggest engine you can work wonders for performance and gives the boat/car that alive feeling. my current 4.4 bmw is far more economical than the 2.8 i had a few years ago and a lot faster and more relaxed.
so it is a balance to what you are putting 50hp onto the back of..
for punch and grunt, holeshot and popping onto the plane are usually easier with a 2 stroke.
i have a yam 15 two stroke and would never ever ever swap it for a 4 stroke equivilent as the yam will always be more gutsy
if you were comparing to bikes then in small and also specialised bikes then 2 stroke is king but for large road bikes 4 stroke is king by far for me
only two stroke i have is a gas gas
not sure if that helps you or not
Originally Posted by ian parkes
I guess that is what Iam having a problem understanding .
I have lots of experiance of 2 stroke bikes and understand the revs and instant power a 2 stroke produces . But even my little 20hp reaches max revs before the boat gets there .
To me 50 hp is 50 hp. I can't understand where the difference can be unless the 2 stroke is able to turn a bigger prop .
If I were looking at bike engines I would compare the torque and BHP figures at a given rpm . Boat engine manufacturers dont' seem to quote these figures and looking at CCs per HP they are not very highly tuned or high revving at all.
I guess if I could go into an outboard shop and test drive each engine on my boat then I could for sure understand and make an imformed choice . But unlike bikes and cars i don't think you can do this with outboards .