What's your rpm set to?

['74 Sport]

This is for you guys running Super Six slants with a Carter BBD 2bbl. When warmed up to normal operating temperature, what is your idle speed set to in PARK and then what does it drop to when in gear?

I tried tuning the carb to 750 rpm in PARK, but once I put it in gear and turn on headlights, it drops down too low for my liking. I now have it set around 810-820 in PARK, and it drops to about 600 in gear. That allows it to have a decent idle at stop lights - not like it wants to die.

Next, what about fast idle rpm while on the high speed choke cam for warming up? In other words, about how many turns on the high speed screw did you go just after contacting the cam?

Finally, how many turns "out" (richer) do you have your idle mix screws? I started with 2-1/2, but the engine would barely stay running. I think I now have them out about 5-6 turns. I smells like it is too rich.

If it is running too rich, would that cause it to diesel. For now, don't consider it to be a timing issue.

As you can see, I'm still having to tweak this replacement carb to find a good combination of choke, choke pull off, high speed idle, curb idle, and air/fuel mix adjustments.

Just wondering,
Jerry

 

[player1up]

I had a similar problem with the idle on my slant. I ended up setting it in gear at about 600 and whatever it went to in N was cool. I really ended up like yours is set:
600 in gear 830 in park ( kinda hard to tell with a sunpro mini )

My idle mixture screws are set at 3.5 turns out, any further than 4.5 and it doesn't make the idle go up just makes it smoke.

Keep in mind:
if you change the timing you have to reset the idle.
if you change the idle, you may have to fool with the mixture.
if you change the mixture you may have to change the timing or idle.

What I did was set the timing where it "felt" best (about 9*) off the line wise and dialed everything to run as best as possible with the timing I wanted.

I recommend:
1. Setting the initial timing to 5* BTDC - this will get you in the ball park
2. Setting the mixture screws to 4 turns out.
3. Set idle where it's happy.

If you have the mixture screws 5-6 turns out to make it run and it diesels, it's a vac leak. ( mine was )

My choke is disconnected, can't help with that.

 

[66aCUDA]

Jerry
Your Idle RPM's look like mine. I think the fast idle is about 1k to 1500 but have never checked it. I do know that the HEI on one of my trucks allows me to run a little slower rpm.
If you need me to I can check on the settings for the carbs.
Frank