Carb Tuning Question

[DenverColoradoFJ60]

Just rebuilt my carb, installed it and somehow it runs! hah

two questions for yall to complete this long journey:

Can you adjust the idle mix screw with the air intake (just the top off) while its running ?
I got to the idle speed screw, just worried the vacuum wont be correct if the air intake is not sealed. I watched the video on youtube but thats an FJ40

second the high idle screw is for the choke when its fully closed right ? what rpm should this be at ?

My idle is around 1k right now and need to get it down about another 300 rpm, thinking i need to lean it out a tad and get the idle screw set

I know lean drop blah blah

 

[2mbb]

I've never been able to access the idle mixture screw with the air cleaner on. I usually take the air cleaner assembly completely off the carburetor and set it aside with the vacuum hoses still connected (air injection hoses have to come off however). I think it is worth it to do the Lean Drop method or something similar (optimizing intake manifold vacuum at idle). After bench setting the idle mixture screw counterclockwise two turns from seated, I find I actually make the mixture more rich to get the correct fuel:air mixture. This will increase the idle speed, and then you back off the idle speed screw. It is an iterative process.

I found this procedure in the 1986 Land Cruiser Maintenance Procedures Manual. I've never actually tried this:

When I've completely torn down my carburetor for a rebuild, I have done the procedure below, which comes out of the 2F Engine Repair manual. It does require a special tool, which is a piece of wire that is 1.3mm in diameter for measuring the gap between the the primary throttle plate and the primary bore wall when the choke is pulled out.

 

[DenverColoradoFJ60]

Yea theres no way to get to the idle mix screw, Ill give it a shot with the air cleaner off.

So it sounds like with choke fully out RPM should be around 1800

thank you for all this

 

[Spike Strip]

You can access the mix screw with the Air cleaner on if you use a long skinny screwdriver. This is what I use LINKY

However, it takes a bit of work to lean over the fender and have enough light to see where the screwdriver blade is, so what I do as an alternative is remove the AC and plug all the appropriate hoses per the FSM and then use a small 5.5oz empty cat-food can with about 5-10 small holes in it to simulate the restriction of the AC. That size cat food can fits perfection over the carb.

I use the A/F meter for the rest of the tuning. Works great.