Fuel System: idle problem

[jif988]

Can anyone help with an idle problem on my 64 Avanti R-2? Everything in the fuel/ignition/engine mechanical is new or rebuilt, car starts immediately runs strong has good compression and vacuum, but won't idle at stoplight etc until the engine is good and warm, temp gauge 160 or so or higher. I tried setting choke two or three notches richer which didn't help....any ideas on what might be causing this? Any suggestions would be most welcome..thanks..Lance

[Mike Van Veghten]

Not much detail here to go by, but.

Have you tried..readjusting your idle mixture screws ? A 1/4 or a 1/2 a turn could go a long way.
Also, is your ignition timing "by the book" or have you increased it at least 4 degrees for an increase in all areas of the way the engine runs.

Then there are the problem areas. This could be a small vacuum leak. All the vacuum ports connected, with good condition hoses/lines, connected to properly working vacuum points of use ?
Have you used the sheet metal intake manifold gaskets with milled heads or block ? A small angular difference happens during this milling/surfacing. The sheet metal gaskets can't always keep things sealed properly.

Mike

[jif988]

Hi Mike, are you saying that the ignition should be 4 degrees ahead of what the manual calls for? I would be a little afraid of detonation or hard starting...As far as vacuum leaks, I don't think I have any as I hooked up a high quality gauge and get a steady 20 inches of vacuum. I'm using regular neoprene type intake manifold gaskets ditto under the carb. It's an Edelbrock 1406 with the top piece from my old Carter AFB which I had to do to accommodate the supercharger bonnet. I did block off the manifold heat passages because I was getting fuel boil over after a long run on hot days and that cured that problem, but now my manifold probably doesn't heat up as soon as it would normally. I haven't tried to change the idle screw settings....would you think I should go leaner? richer? thanks....Lance

[Jeffry Cassel]

If timing is off, it will not idle down properly. Local shop had timing spot on and 64 Hawk wasn't right. Took it to Gary, who is nearly as old as I am, and he adjusted it to where it is absolutely perfect by finally calibrated ear. I don't think you can use timing marks for anything but a starting point with today's crap gas. Try to find a good mechanic who is over 60! (My car has an Edelbrock 1406-great carb!)

[altair]

I think you are experiencing carburetor ice, the fact that you have blocked off the heat crossover system that is designed to counter carb ice is most likely your problem. No adjustments will fix it, the only fix is heat to melt the ice. On cool days with high humidity a little longer idle before starting off or use a block heater will most likely cure the problem. When the humidity is very low the problem will be lesser and as the humidity increases so will the problem.

[Xcalibur]

My experience typically suggests faulty carb in some way: worn-out, missing pieces, etc.

[63 R2 Hawk]

Was the Carter/Edelbrock hybrid known to be working OK at one time? Have you checked to make sure floats haven't collapsed under boost pressure? Could be a metering size problem? Sealing issue? My R2 has never run right using factory specs, it needs a minimum of 12 degrees advanced over spec to even begin to run right, even with today's junk fuels. As mentioned, spec is a good starting point. From that point, I use my ears and have never had any issues doing it that way for the past almost 60 years now. I just hope my ears will keep working as long as I own and drive vintage cars... BTW, I just started a thread about R2 timing today, I always get concerned when stuff doesn't work right when it's set up " by the book".

[bezhawk]

[QUOTE=jif988;1080747 I haven't tried to change the idle screw settings....would you think I should go leaner? richer? thanks....Lance[/QUOTE]
A cold engine always like a richer mixture. Here is how I set initial idle mixture screws. Seat them all the way in (do not force them, you don't want to groove the needle or seat).
Then back off the idle screws 1 and 3/4 turns. This should get you to a point where it idles ok. Then adjust further after it's running to get the smoothest idle..... no matter the idle speed. THEN set the idle speed screw on the linkage.

[Jeffry Cassel]

Carburetor ice?? The thing is sitting on a 600 lb radiator. Have to be 36 deg. with 200% humidity to ice.