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I just adjusted my air/fuel mixture for the idle and low RPM's. Now what I really need is to lean out the mid and high RPM's. How is this done? Is there a screw I can turn to make this happen? Please be descriptive about the location of things on the carb as they are rather complicated (in my eyes at least).

BTW, this is carb is on a '85 truck.

thank you,
 

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I had an 84.....the fuel/air ratio is adjustable by removing the pressed in cap located on the right side of the carb(passenger side).....it is awkward to remove it 'cause it is near the fender and a drill cannot fit in the space....but a sharp pointed chisel will.
 

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Originally posted by ZUK:
<STRONG>I had an 84.....the fuel/air ratio is adjustable by removing the pressed in cap located on the right side of the carb(passenger side).....it is awkward to remove it 'cause it is near the fender and a drill cannot fit in the space....but a sharp pointed chisel will.</STRONG>
If I am not mistaken, the brass screw found under the pressed in cap is for adjusting the IDLE mixture. It does not vary the mixture for off-idle or wide open throttle positions. At that point, systems such as the power valve and secondary metering rod and jet system are the factors determining fuel/air ratio. The idle mixture adjustment is particularly ineffective at wide open throttle, as there is so little vacuum to draw fuel through the idle system anyway.
 

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Originally posted by liveaxle:
<STRONG>I just adjusted my air/fuel mixture for the idle and low RPM's. Now what I really need is to lean out the mid and high RPM's. How is this done? Is there a screw I can turn to make this happen? Please be descriptive about the location of things on the carb as they are rather complicated (in my eyes at least).

BTW, this is carb is on a '85 truck.

thank you,</STRONG>

The rest of the rpm range is *basically* controlled by jets - which are little brass things with measured holes in them that the fuel flows through. Bigger holes equal more fuel flow for a given airflow. Basically.

So, if it is too rich in the higher rpms, you might want to go one size smaller on main jets. I can't remember if Toyota sells these or not (probably not) because it has been years since I worked in the dealership, but there is another trick I have seen. <IMG SRC="smilies/biggrin.gif" border="0">

You can actually solder the jet shut & use specialized jet drills or reamers to get it back out to the right size.

Worth a try!
 
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