Yamaha 6 hp 2 stroke vs. 8 hp 2 stroke

[lat]

Hi, can anyone tell me the difference between these two motors ( 2004 + ) in order to achieve the extra 2 hp. Is it the carb/ jetting ?, throttle set- up ?
If i compare the " spec" sheets they are identical . i tried the parts list #s for carb assy. but can only find the 8 hp #'s.
The price diff is about 400. from 6 to 8 hp. ( 2008 ) Both weigh 60 lbs.
I'd like the extra 2 hp , so not sure if i can widen my search to 6 hp as well?

 

[01286p]

Re: Yamaha 6 hp 2 stroke vs. 8 hp 2 stroke

I understand that there are two small differences.
1) The carburettor jets need changing.
2) A small hole needs to be drilled in the exhaust manifold.

You can probably get the details from your Yamaha agent.
The change over is very easy.

 

[robert graham]

Re: Yamaha 6 hp 2 stroke vs. 8 hp 2 stroke

May be a difference in the size, shape and location of the cylinder ports. Jet sizes, compression ratios, exhaust system are areas where very minor differences may exist. From 6HP to 8HP is a 30% increase! My 90HP Yamaha 2 stroke has a different compression ratio in each of the 3 cylinders...Go figure. I doubt that I would ever try to "hot-rod" one of these motors unless I really knew for sure from a reliable source what changes were required. Good Luck!