4 stroke air /fuel screw setting

[jerryjerry05]

2005 250 Yam 4stroke.
My friend thinks he knows how to set these screws.
He saw somebody do it using the gauges and says he can do without
them.
It's his motor and it runs like crap at low speed.
Anyone know how or if it's printed how to do it someplace?
Thanks

 

[stresspoint]

this should be interesting .

as far as i know the idle air screw needs to be set with the ECU in set mode to allow the idle air control (IAC) to co ordinate with other relevant sensors.,
so pretty much would be hit or miss if you get the air valve (screw) set correctly.

 

[jerryjerry05]

That's what I thought.
When I saw him adjusting it by EAR I thought he's in for it now.

 

[boscoe99]

Interesting.

The Yamaha F250 has an electronic throttle valve. It does not have an idle air control valve.

 

[Lou C]

You can do that on old carbed motors but anything with electronic control….don’t think so!