Air/Fuel Mixture screw

[BoisBlancBoy]

Does anyone know what direction, tightening or loosening the air/fuel mixture screw corresponds to richening or leaning it out?

[1FST690]

When you screw it in until snig and then start backing it out, the farther you back it out the richer it will be

[BoisBlancBoy]

Hey guys, I just ran my rig on a new plug for the first time for about 10 minutes.  I pulled the plug and its hasnt darkened much at all, so this means running lean right?

So I already have the air/fuel mixture screw out 3 turns, should I go half turns out until I get the perfect chocolate color?

[BoisBlancBoy]

Alright guys since I got impatient waiting for an answer this is what I did.

I changed the mixture screw and ran it for at least 10 minutes each ride on settings of 2 1/2, 3 and 4, with no color left on my plug.  I also set the mixture screw at 2 and the machine wouldnt even start.

So I am at a complete lose right now.  Whats the deal?

Could this mean I am not jetted large enough?

[Flynbyu]

What are your jet settings again?

~Brian

[BoisBlancBoy]

155 Main
25 Pilot

[Flynbyu]

You're at 2 turns and it won't start?

~Brian

[BoisBlancBoy]

Yeah at 2 turns out it wouldnt start, so I set it at 2 1/2 and it would run fine.  I have also run it at 3 and 4 turns out, ran fine there as well.

[Flynbyu]

Yeah at 2 turns out it wouldnt start, so I set it at 2 1/2 and it would run fine.  I have also run it at 3 and 4 turns out, ran fine there as well.

At 2.5 turns you don't have any hesitation through the gears?

~Brian

[BoisBlancBoy]

If there was, it wasnt much.  Whats your thinking if I do have some hesitation at 2.5?  I have only riden it just a couple miles at 2.5.

[Flynbyu]

If you're okay at 2.5 turns and you have no hesitation in the throttle going through all the gears then you are in good shape.

Do you know how to read your plug?

~Brian

[BoisBlancBoy]

Yeah but so far the half hour total on my plug hasnt shown anything.   how long of a ride do I need before I will know one way or the other?

[Flynbyu]

Yeah but so far the half hour total on my plug hasnt shown anything.   how long of a ride do I need before I will know one way or the other?

I was told to install  the new plug, go through the gears at high speeds, and kill the engine. Pull them plug and read.

If it's super black, or it's a nice light brown around the porcelain at the electrode you're in good shape.

~Brian

[BoisBlancBoy]

Well so far, the plug and porcelain looks brand new!!!  Thats why I am so stumped.

[1FST690]

Air/fuel screw wont do much through the rpm range. If there is still no color on the plug. Jet to 160 and retry the plug reading. WFO in like third, cut engine, stop pull plug and check.