Fast Idle and Automatic Choke adjustment.

[Dimitri13]

Hey guys, I finally got my manual, but the directions for both of these are a bit unclear to me as I've never done them before on cars. Well, I've never done either of them on bikes either because the carbs on my bike are ooooold and very basic.

It's a quadrajet M4MC.

Does anyone have a walkthrough, hopefully with detailed pictures and explanations?

Thanks in advance.

[BillyJack]

Since I'm at work and not close to a manual, I can't quote you fast idle specs. Many, many years ago, my late father, a lifelong auto mechanic and service manager taught me some basics of choke adjustment that have served me well for years.
Set the choke thermostat so the choke blade is just barely closed at 60-70 degrees ambient temperature.
Using a drill bit or allen wrench as a gage, adjust the primary vacuum break until it pulls the choke open 1/8 inch. If that particular carb has a delayed secondary vacuum break, adjust it to open the choke 1/4". That will put you in the ballpark. Once you've put it through a few cooldown and drive cycles, adjust from there in small increments depending on driveability characteristics.

Bill

[Dimitri13]

Alright guys, I figured out my choke issue. I had the tang of the thermostatic coil outside of the slit where it goes. My issue now is (possibly) the fast idle. It idles high like it should in Park (around 13-1500 RPM), but when I put it in gear, it'll slow down to very slow, like 3-400 RPM (I don't have a tach to check atm). And no amount of feathering the throttle would fix it, and any revving would cause it to stumble and die. I've tried adjusting both the fast idle and regular idle screw, but no amount of adjustment in either direction would help. It was so bad that putting it in drive to trying and scoot it up in the driveway (it's a very slight incline) would cause it to stall out immediately.

I'm pretty fed up with it and may just get a Mountain Man carb, but I'd realllllly like to fix this issue.