Which outboard motor for 22' Tri?

Thanks Dennis

I would avoid the 9.9 due to the additonal weight hanging off the transom but the 9.8 2-stroke would give the best power to weight ratio.

There was a guy in Sydney who wanted to swap his 9.8 for a 5 to avoid rego issues but he declined to swap for my 6 Hp - pity. As stated, I'll have to see how the 6 goes for the time being

Alan

 

Yeah, just keep your eye out on gum tree etc and you will find one for a good price eventually.

 

The 4 stroke is the newer engine, generally they deliver higher thrust and better fuel efficiency at displacement speed for any given HP. Typically more torque swinging a bigger higher thrust prop. The 6 should shove you along as fast as the 9.8, on a yacht at least, and you should feel the difference when pushing wind and current. Also many countries are outlawing the two strokes so I guess Oz will follow eventually.

2013 sucked... big time. Roll on 2014

 

This goes against everything I thought I knew regarding 2 vs 4 stroke. I always thought a 2 stroke of the same peak power had far more of its power available over a wider RPM range, IE more average power so will be faster. If we are banning them its even more reason to get one now before you no longer can.

Good comparison here. http://continuouswave.com/ubb/Forum4/HTML/007938.html

 

Generally a 4 stroke will have more torque and push that an equivalent HP 2 stroke. So a 6hp 4Stroke would probably be roughly equivalent to an 8hp 2 stroke with the same shaft lenghth and prop. I run a 2S 5 hp Merc LS on my 25' tri. it will push the boat into 25 knot headwinds on about 3/4 throttle at around 5 knots. No wind flat out = 6.5 knots. I would describe it as adequate. When it dies I will probably replace it with one of these.....
http://bridgeyachts.com/index.php?product=MFS6CUL

 

Maybe I have missed something, but I understood the newer 2 strokes were far more environmentally acceptable than the old ones and are likely to remain available in OZ for some time to come. Anyone know differently?

 

I dunno, that maybe true for higher speed applications... all I know is that the four strokes are normally setup better for low speed applications and have more torque lower down. Seawind 1000 typically uses 2x 9.9 hp four strokes and that is around 5 ton of boat with big windage. I think that the power is up high in the rev range with most two strokes so they swing smaller faster props where as four stokes deliver down low and can swing larger slower props. Wrong terminology I am sure but you get what I mean!

On a 16' tinny an equivalent hp 4 stroke probably won't touch a 2 stroke but on a 24' yacht the opposite is probably true.

Two strokes are getting the chop because of the oil in the fuel getting into the water with all the nasties that entails... or so I am told! I googled it an read that it was not a ban as such but that they can't be made to meet the newer emissions standards (requires oil injection I believe!). I guess we lag the Euronuts and Yanks in that department, so I guess it will come our way sooner or later.

 

It probably has more to do with the global market. They make engines to suit the strictest of the major markets, that way they can sell them everywhere. That is why our cars are built to spec's dictated by Californian law, I guess it is the same with marine motors.