How do you adjust and which screw is the Idle air mixture screw?

SOURCE: ryobi 31cc lawn trimmer carb adjustment

As with all 2 strokes if you have compression and a reasonable spark, you only need fresh fuel with correct oil ratio) and they must go !(as long as you haven't fiddled first and all gaskets are sealing) I start mine by(1) pumping the primer till it is firm,(2) full choke,(3) pull till it kicks ONCE,(4) half choke, pull till it runs,allow to warm up and(5) switch to run (you may need to apply a bit of throttle while pulling as in (4)(or give it a few more pumps if it dies) If all is ok, check that when properly warmed up there is a smooth transition from idle to full revs, if it hesitates it may need the LOW SPEED mixture leaning (clockwise) SLIGHTLY.If it dies the LOW SPEED mixture may need richening(anti-clockwise)(adjust 1/8 turn at a time) Make sure that motor is just peaking at full revs and is on the RICH side of peaking (HIGH SPEED mixture)(this will avoid seizing it Adjust both till it revs cleanly and is JUST rich at full, and idleing nicely and it should start without too much trouble.(If you have fiddled and are lost,-about 2 1/2 turns out from closed on both needles should get you started)

SOURCE: mixture screw problem

This is confusing sorry. There are two screw, outside one and an inside one. Do I:

a) Screw them all the way in and then both out 1 & 1/2 turns

b) Screw them all the way in, outside 1 turn and inside 1/2 turn

c) Screw them all the way in, inside 1 turn and outside 1/2 turn

d) e) f) all of the above but screw them all the way out and then turn back in

Thanks for your help

SOURCE: Hello I'm fixing my poulan pro ppb200 gas

My service center told me that they are allowed only 2 of these adjuster per year. It has to do with the air quality issue. They don't want back-yard fixer-uppers to pollute the place up. True store - I could not believe it.

The BLUE wire-splice connector, the one that you crimp after you put a wire in each end, is supposed to fit snug around those screws and allow you to adjust them. However I could not get it to work.

If you take a hack saw and cut the lip from around the adjuster screws and then cut a slot in the adjuster screws themselves, you will be able to set those screws with a flat-head screwdriver.

The whole operation takes about 9 pushes of the hacksaw. The lip is aluminum and the set screws are a very soft steel.

Good luck
John

SOURCE: mcculoch mt 300mcculoch petrol strimmer carb two

Actually both screws are for petrol mix. The screw closest to the engine is the Lo side. Lo side jet provides petrol at idle and during the ramp up to speed. Hi side jet (closest to air filter) only effects the mix at high speed.
From McCulloch, these were set at 1 1/4 turns out.
Good luck!

SOURCE: How do you adjust the high speed mixture screw? I

Hi montex124, I will try to help. In the past few years carb makers have been making changes. Some carbs have no adjustment at all, the ports are all fixed inside the carb. Other carbs have only the idle speed mixture screw that can be adjusted, like yours seems to have. Is this screw you mention at the top and completely outside of the carb to adjust the throttle? If it is it's probably the idle speed screw which can be adjusted to any idle speed you want and has nothing to do with the air fuel mixture but If it is right next to the idle mixture screw, it might be the high speed mixture screw but is capped so it can't be adjusted. The low and high speed mixture screws should be marked next to each screw H and L.
The 1 1/2 turns suggested is sometimes just right but other times has to be adjusted, so you can try adjusting it to get your idle but maybe adjust the idle speed screw first to get a higher RPM so it doesn't stall on you. Like I said earlier it just adjusts the throttle, and is like when you are using it, and giving it gas as they say. I hope this helps just a bit. Regards and good luck. Get back to me if you need more help or just let me know how you did. Denis.