Carburator problem

[JimNolan]

Guys,
   I got a problem. It's OK now but I'm thinking it'll happen again. I was cruising the other day when the idle on the engine went up to 1500 and stayed there. It was warmed up so I knew it wasn't the fast idle on the choke. The car ran OK, it just idled at 1500 rpm. Here's what I HAD to do to get it down the 900 rpm.
1.  Screwed the throttle adjust ALL the way out. ( ButterFly was completely closed )
2.  Screwed the two idle adjust screws ALL the way in to the stops. ( Lean )
3.  Screwed the fast idle adjustment screw all the way out of the carb.
4.  Decreased the ignition timing to 0 degrees.
Then it would idle at 900 rpm but ran like crap. The manifold pressure was down to 14 inchs at idle.
TODAY: I checked that there were no intake leaks ( starter fluid ) I replaced the carb gaskets just for insurance. Then, I took it out for a drive. It ran like crap and blew out all kinds of black smoke out the exhaust. I then floored the accelerator and went through gears real hard. When I came to a stop it wouldn't idle at all and ran like crap. I then went back and adjusted the throttle adjust screw to idle at 650 rpm, I adjusted the timing back to 7 degress BTC and turned the idle adjust screws back out to obtain optimum vacuum. It runs great and idles at 650 rpm very smoothly while maintaining 17 inches manifold pressure at idle. JUST LIKE BEFORE.
WHAT HAPPENED. I'm figuring if it happened once it'll happen again. Jim

[wolfpupsdad]

 jim, did ya notice if the water temp went up? thats an indecation od a lean out, black smoke is rich condition, i'd say off hand if ya had no air leaks, and not know what carb or how old of a carb , i'd say off hand , dirt in the metering circuit of varnish . thats where my head takes me.

[4banger]

Go back to basic's and make sure the rotor is pointing to # 1 on the cap on the compression stroke at TDC. A chance it may have jumped timing.

[4banger]

Or vacuum advance isn't working properly. Unless you run mechanical.

[shopratwoody]

I'd have to agree with the dirt or varnish thing. I wouldn't be changing timing because
of this. Check it but don't change it. Maybe put some additive in the gas tank. Probably
something simple. Hope it doesn't happen again.
later, Ron

[JimNolan]

Guys,
   General consenses that indicate metering circuit contamination is probably right. I went to a Car Club meeting last night and talked to the head GURU that has a garage for high performance cars in Warsaw. When I told him what happened he just smiled and said " You need to blow out the cobwebs every now and then ". I have a two year old Holley Street Avenger and he claims that the Edelbrock 4 barrel is the worst when it comes to circuit contamination.
   This morning I'm going to install another fuel filter between the fuel pump filter and the carburator. I always considered the old saying " blowing the soot out of the carburator" just a wives tale. So, I'll go through gears more often. Also, my car sat for about a month this year that I wouldn't put it on the highway. Varnish could have built up and broken loose. Fuel additive might help too.
Thanks for the response guys. Jim

[Hoosier Hurricane]

Jim:

Can you stand one more suggestion?  I know you're not running a teapot, but I have had the secondary throttles fail to close completely at times on them.  Made the engine idle fast.

John

[JimNolan]

John,
    I'll keep that in mind if it happens again. I'm running the stiffest spring in the vacuum cannister. I never thought of the secondary but it makes a lot of sense. Thanks, Jim

[JPotter57]

Indiana is probably switching from winter fuels to summer, and as such probably has more alky in it.  Just a hunch, never can tell with the way they brew our fuels these days.  You may have just picked up a bad load of gas, water or other contaminants..  Check your fuel while you're checking other stuff.

[JimNolan]

Guys,
  My carburater problem. Went away. I think I figured it out.
The dual springs I had put on the throttle return for drag racing at Gulfport were left on it. I think that was too much tension on the throttle plate and it bound up at times. I removed one of the springs and haven't had any trouble since. Just thought I'd get this in. Jim

[wolfpupsdad]

 well like ron said, " it's probably something simple",and why the hell do we over think things, lol. glad to hear ya got the problem solved.