1911 L-jet. How to get a good Idle., What to do get a 900 to 1000 rpm idle? Options

[tach]

I can not seem to get the idle where it should be. Its idle is either to high 1350 rpm or to low, as to where it will eventually quit running. The engine runs great with plenty of steady power thru out the power band.

What to do get a 850 to 1000 rpm idle?

1974 1.8 with these modifications.
1974 1.8 with larger pistons Keith Black pistons 1911
Stock L-jet.
8.2:1 CR.
Stock Bosch injectors.
Raby 9590 cam kit.
96mm Keith Black flat top pistons.
Stock distributor-Pertronix.
Stock heads, valves and valve diameters.
1.8 SS heat exchangers.
Triad Exhaust.
Newly rebuild engine.

[jcd914]

I would probably check the distributor and see if the centrifugal advance mechanism is hanging up or maybe the vacuum advance & points plate.
Some times they get sticky and hang advanced some as the engine comes down to idle. With the timing advanced (cause it hung up) the engine idles high. If you adjust it down lower the advance finally releases and timing drops to where it should be but now with the idle set low and the timing no longer advanced, it won't stay running.

Use a timing light to see what the timing does as the engine come down to idles and below.

Jim

[Valy]

I don't agree the distributor is the problem as the timing is set at idle on LJet.
Here is what you need to do, in this sequence.
1. Do valve adjustment.
2. Make sure there are absolutely no vacuum leaks.
3. Adjust timing at idle, all distributor vacuum lines disconnected and plugged.
4. Adjust idle screw at AFM
5. Check 3 and 4 again if necessary.

Keep in mind that the cam you have doesn't like low iddle so you will probably need to compromise for a slightly higher idle.

[timothy_nd28]

(IMG:style_emoticons/default/agree.gif) mostly with what Valy said except the AFM adjustment. Idle adjustment is typically done on a big adjustment screw on the throttle body. The AFM adjustment screw really shouldn't be messed with, unless you have an AF gauge and have read the AFM pdf bible 3-4 times. Black22 has this pdf, if you PM him, I'm sure he will share with you.

Being that you have a 1911 (so do I), you may have to mess with the AFM anyways to loosen the clock spring a few teeth, to richen the mixture. With that said, save this step until the last resort.

Follow Valy's suggestions except the AFM adjustment. Then, I would temporary remove the aux air valve from the system by removing the hoses and capping the plenum with a rubber cap, and cap the plastic T at the S boot. This will help isolate what I think may be causing your issue.

[Root_Werks]

I don't recall what page it starts, but I converted a 2.0 from carbs to L-Jet. It takes some adjustment to get things smooth and correct, but it can be done. I'd wager a 1911 would be closer to a 1.8 than a 2.0.

http://www.914world.com/bbs2/index.php?sho...104990&st=0