The 35 cubic inch versions could run 70 hp Yamaha carburetors. The 31 cubic inch models which is the original displacement ran very well with 40 hp tohatsu carburetors. Especially the tohatsu carbs with the fuel pump mounted on the carburetor. Replacing the 30 reed cages with 40 Yamaha cages was necessary.
The SLT group are big fans of this carburetor selection.
https://www.youtube.com/shorts/9c7AWT7CGp8The hunt for 40 reed cages was easy. The hunt for a good set of tohatsu carbs difficult.
But I now have both.
The gearcase is now assembled and I think I have enough spare 30 hp Yamaha parts to build a short shaft with both manual and electric start.
Once I can get it testing. Then I will see if it can benefit with more changes.
There is a fine line with any mod outboard. Just get a bit to extreme and the performance drops.
The good part with these 30 6J8 Yamahas is the mods improve every aspect of the motor’s performance. Hopefully my motor won’t be a disappointment!