Dunno ebb,

My old Yamaha 6 hp worked well with the stock (7x8 IIRC) prop, when I switched to the 'high thrust' (also 6x8) mickey mouse ear prop the rpm did not change, but the backing was improved.

When I bought the tohatsu, I tried it with the stock prop which was something like 7x8, I was underwhenmed with this, it did not seem to want to turn up, so I poped for the expensive 5.99 x 8 'high thrust' prop (you can see the details earlier in this thread)... it was not much better.

I suspect I might have been happy with the tohatsu, had I not been spoiled by the Yamaha. I really think your answer of the 8hp (2 cyl) Yamaha with the high thrust arrangement is probably going to prove to be a wonderful motor for Lil Gull. I am glad many others find the 4 stroke Merc/Nissan/Tohatsu solution to work out for them... I am not happy with it myself.

I will do some testing with both motors though, I expect to conduct some rather scientific experiments where I force myself to motor a standard course with both (one at a time of course) to prove out the fuel use issue.

It is interesting to note, the 4 stroke has to work well higher in the RPM range to acheive hull speed then the 2 stroke did... I suspect this will negate some of the fuel savings. I KNOW from experience that the (2 cyl) 2 stroke is smoother then the (1 cyl) 4 stroke... and frankly I doubt that it is any louder (maybe I can barrow a db meter to see for sure). The Yamaha always reminded me of a cyl diesel with it's mechanical drone... not un unpleasant sound to me.

We will see, stay tuned for further updates... if nothing else, I do tend to go on (and sometimes on and on) about what ever I find.