Yamaha 20 HP 1992, Carb issues.

[NiklasES]

Hi all.

I bought a boat a few days back. with a Yamaha 20HP from 1992. It was a bit of a gamble, due to that the engine doesnt work as it should. the prevoius owner had the carbs sent for cleaning. And now i goes really good on low rpm and high rpm, but dies there between. I was woundering if anyone have a repair manual, or know how to reset the carbs to orginal (think hes been trying some settings without knowning really how to it)

Have a great day / Niklas

[NiklasES]

Sweden, and your right. My bad english gave that away i guess got a pic of the model.

[NiklasES]

[99yam40]

I do not see a 20hp listed in 1992 for here in the USA, so finding a service manual and settings here maybe very hard.
have you checked around in your country for a manual?
20DMO
6L3 L 401935 B

maybe Boscoe can come up with a motor close to that here in the US

[boscoe99]

A USA model 20MLHU is also a 6L3 prefix model. I suspect that the parts for this model will work on the OP's motor.

https://www.boats.net/catalog/yamaha...ar/1997/20mlhv

The baseline setting for the idle mixture screws (aka pilot screws) is 2.5 turns outwards from being lightly seated. Plus or minus 1/4 turn.

My guess is that the carburetors are still not properly cleaned. SM can be purchased from this website.

https://www.boats.net/search?q=lit-18616-01-36

[NiklasES]

Thanks you very much for all your help.