Completely stumped: High Idle Carby

[scitzz]

Daughters car. 1989 Carb Manual. Idles at around 2500 RPM. Choke was doing absolutely nothing so I replaced the entire Carb, mounting gaskets. Still idles high but you can see choke movement. If I manually close the choke the idle comes down. Spraying carb cleaner everywhere, no change in idle. Can not find a vacuum leak. Started replacing any vacuum hose that seemed the slightest bit loose. No change. swapped out the high altitude compensation thing, whatever the heck it is called. No change.

If I rev the engine, sometimes the idle will stick at 3 grand.

Ideas?

[TominMO]

I assume you checked that the throttle cable isn't too tight, and moves freely in the cable housing?

So manually closing the choke does bring it down to where it should be? I wonder what would be keeping it open then; that seems to be the problem. Maybe a bad choke diaphragm?

[bravekozak]

It's a feedback carb. I've seen that happen before. I believe it's due to a vacuum problem. I have no idea which line.

[zoe60]

Sure you are getting voltage to the electric choke?

[scitzz]

Yep. I have been thinking vacuum, but can't find a leak. Might be planning a Weber swap, this is for the birds.

Running around outside the asylum again with my tappy talky appy

[nitrofarm]

Ideas?

Is the Choke really receiving the proper amps to pull the the choke open.
Assuming that the hoses are good because you checked them during removal/re-install.

[scitzz]

It's getting the seven volts the manual calls for. The natural position is closed, it opens and moves a little.

Running around outside the asylum again with my tappy talky appy

[nitrofarm]

Yes volts but power like amps? New carb does the same thing. So is the choke getting proper amps (Green corrosion @ Alt terminal)or is the return spring junk. Or is a hose leaking big time. Doubt if both Carbs has same problem,but I had 3 bad used starters in a row so I guess anything is possible.

[scitzz]

No corrosion. Return spring seems fine. I have sprayed Carb cleaner everywhere. No leaks to be found.

Running around outside the asylum again with my tappy talky appy

[nitrofarm]

IDK intake flange is warped and distorting the carb butterfly shaft when you torque it down??? Interesting how the problem followed the NEW used carb. Out of ideas Scitzz-

[scitzz]

IDK intake flange is warped and distorting the carb butterfly shaft when you torque it down??? Interesting how the problem followed the NEW used carb. Out of ideas Scitzz-

Exactly my thought so I chased vacuum.

*sigh*

Running around outside the asylum again with my tappy talky appy

[scitzz]

Anybody else find it strange it idles down when I close the butterfly?

Running around outside the asylum again with my tappy talky appy

[tooldude]

Anybody else find it strange it idles down when I close the butterfly?

Running around outside the asylum again with my tappy talky appy

Not really, because that makes me think that you have a vacuum leak and manually choking off the air to the carb intake is cutting down on the extra air. I'm confident you know how to check vacuum hoses, but do you have a hand vacuum pump to check the various vacuum diaphrams that are on the carby? You need to check all of them, including the advance diaphram on the distributor (that one leaking caused my engine to act a lot like yours). You could pull the hoses off the ABCV cannister on the carb and plug them (don't mix them up) in case the air bleed valves are stuck open. I'm not positive they can bleed that much air but it's an easy check.

[nitrofarm]

Anybody else find it strange it idles down when I close the butterfly?

Running around outside the asylum again with my tappy talky appy

Not strange at all,"Feedback Carb" = strange though. But what is curious is that the problem stayed with your replacement. Thats why I guessed return springs or throttle cable binding. So many vacuum lines on those though feed-crap Carbs,so maybe a crack at a nipple would/could cause less pull on a "idle down diaphragm"???

[tooldude]

If you give up on a stock carb and put on a Weber, I need those thermo vacuum valves under the intake manifold, if they work.