Yamaha 50 2 stroke

[rig_dude]

Hi all,
I am a newbie here and wanted to pick your brains for a sec.

My 4.3 Quintrex has a 2002 50hp 2 stroke, and I was wondering if the rumor I heard was true about being able to change something in the fuel system to make it the equivalent of the 60 hp. Is this able to be done, and do you think it worth the trouble?

Cheers :)

[BaitThrower]

Isnt it ususally changing the carburettor, or more serious, reboring the cylinders how you get higher HP? Something like that. But more importantly, 50Hp isnt big enough for your 4.3m quinny?

[wiz]

Mate if it was as easy as that do you think the manufacturer would bother making the different models???
There is the intake and the outake that has to be considered and each HP is designed accordingly, reguardless of the same bore and stroke.
They would loose to much money if it was as simple as a rejet or like wise.
do a search and you will get the answer to your question
cheers

[snelly1971]

Hi all,
I am a newbie here and wanted to pick your brains for a sec.

My 4.3 Quintrex has a 2002 50hp 2 stroke, and I was wondering if the rumor I heard was true about being able to change something in the fuel system to make it the equivalent of the 60 hp. Is this able to be done, and do you think it worth the trouble?

Cheers :)

Not true with that motor, they are the same as the 40, you can turn 75 hp yammies into nearly 90 with a 90 carb fitted, same goes for the 115 / 130 yammies

Mick

[Scott Ashe]

Hi mate,

I would think that 50HP on a 4.30m Quintrex, would be quick enough.

Cheers
Scott

[Noelm]

a carby change does NOT make a 115HP Yamaha into a 130, try it and see how you go, it is an "urban myth" there is a host of differences in the two Motors.

[flotsom]

you can not go from 50 to 60, they are differant engine types, 698cc to 849cc. so if you just fit larger carbs you would have a host of running issues.

also noelm is correct, 115 is also differant to 130, carbs are not the only differance. same cc's but differant compression ratio, 115 is 6.5 and 130 is 6.8. also timing changes, prop changes, spark plug changes due to timing etc. you can play but have fun getting smooth yamaha performance.

[pursuit001]

same as every one else has said wont work .
cheers

[rig_dude]

Cheers guys,
i will stop chasing that idea then. The 50 goes great on the 4.3, but i do a bit of wake boarding and tubing behind it as well as plenty of fishing. Thought I may have been lucky as she takes a bit to get out of the water with a skier. Once you are up though it pulls along with ease.

[ausandy]

hey guys, this one has been bandied around for years, changing the carbs WONT give you more horse power. to gain more horsepower you have to burn more fuel, get it into the cylinder at a the right time via the port timing. then you have to get the exhaust out at the right time. many times have we had an engine brought to us and have been asked to get it right after it ahd been played with.

yes the 40 and 50 hp share the same block platform as do the 75 thru to 90 and the 115-130 family of motors. but the block is different internally and the exhaust megaphone, and tuning is different.

[Flex]

hey guys, this one has been bandied around for years, changing the carbs WONT give you more horse power. to gain more horsepower you have to burn more fuel, get it into the cylinder at a the right time via the port timing. then you have to get the exhaust out at the right time. many times have we had an engine brought to us and have been asked to get it right after it ahd been played with.

yes the 40 and 50 hp share the same block platform as do the 75 thru to 90 and the 115-130 family of motors. but the block is different internally and the exhaust megaphone, and tuning is different.


Speaking to a Yamaha dealer when I went to buy my 40hp. and compairing it to the 50.

The 50hp is the exact same block, but with different carby AND exhaust on it. They told me it is possible to upgrade it to a 50hp but at a cost of around $1800 or more.

So I paid an extra $400 and got a 50hp off the shelf.

But the 50 and 60 are totally different engines.

If you want more speed look at changing props etc