Originally Posted by Phil Davies
Just what I didn't want to hear, Pitkis! Having decided to keep my SR4 for a while longer, I am about to upgrade my Honda 30 to either an Evinrude 50 ETec 2-stroke direct injection or Suzuki 50 EFi 4-stroke. I have managed a maximum of 26knts in a flat sea with my Honda but am a little disappointed to hear that at only 4knts more the boat becomes unstable. Does this mean I'm wasting my money upgrading to a 50 since my aim is to achieve higher top end as well as better acceleration? I'd be interested in your views before I splash the cash.
How many times are we going to have to go over this Davies ?? bigger engine = more weight + more fuel/additional speed gained = lots more money and not a lot of gain, so ok we can reduce weight by going 2 stroke but the fuel costs increase and more importantly the amount of fuel you have to carry will increase upwards....have you thought of that one to ! remember a litre of petrol weighs in at 1 kilo, so an additional 24 litre container is an added 24 kilos your'll have to carry and of course your'll have to store this added fuel some place on the boat too ?
Why not as a cheaper alternative invest in a higher pitched prop, if you go up two inches and keep the same diametre your'll lose a little take off speed but gain a few knots top end ! so think about it....if you put a 50hp on and its going to cost you say 4-5k to do it and remember you have to have is set correctly on the transom too, and all you gain top end is 5 or 6 knots or you could spend £170 on a stainless prop with a 2 inch gain in pitch and gain say 3-4 knots !!
Also worth remembering your still only in a 4m boat, yep great on flat calm days on the Thames, but its not always flat is it, lots more speed will only make you take off between crests much quicker.
Not trying to put you off Phil in any way, i know your gagging to spend some money but just think about the overall costs longterm, i'm running a thirsty 50hp 2 stroke, when we go out i have to carry more than twice the amount of fuel as you do to get the same distance as you ! and your still managing to keep up with me! thats fact.
In MHO change the engine because its knackered or unreliable or keeps going wrong, but dont chuck it becuase you want a few extra knots, instead sell the complete rig as a good well balanced set up and by an 8 metre Scorpian.