Yamaha F90 Idle adjust screws inital settings

[Timj1960]

I have a 03 Yam F90 I would like to take the 4 idle set screws back to a inital setting. Not the idle mixture screws as they are sealed. but the linkage screws. What I'm looking for is a starting point like the no. of turns from inital contact. Anyone have this info?

 

[99yam40]

Re: Yamaha F90 Idle adjust screws inital settings

The Yamaha manual for your motor should give you a Sync and link or link and sync procedure that will do this. If you do not own one yet, buy one. it will be money well spent for this and all the other info and procedures you need to maintain your motor.

 

[rodbolt]

Re: Yamaha F90 Idle adjust screws inital settings

actually there is NO spec for what you wish to do.
it takes a 4 channel mannometer,like a tech mate Vacum mate.
tool is about 600 dollars, there are a few cheaper.
that and the correct service manual and anyone can do it.
there is only ONE idle screw on that engine. the others are for shutter adjustment.}
basic procedure is to remove the 4 manifold plugs,10mm hex with a copper washer,
install the 4 vacum adapters,install the 4 channel manometer.
start engine and allow it to fully warm up.
set RPM using number 4 carb to 1100 RPM.
now adjust the shutters for carbs 1,2 and 3 so the vacum is equal plus or minus the spec, i cant recall it right off.
so basically engine vacum is adjusted to equal on all 4 at 1100 RPM.
sometimes it takes a couple tries.