Idle is at 1500!

[frank1966]

Sometimes I get so frustrated with these cars always something else!

I have edel carb 440 with an all in one mds distributor which manual says it requires ported vac not  manifold, not sure that is so. I know very little about vacuum and timing, for some reason I can't understand the concept! I cannot get my idle down at all, idle screw all the way out and mixture strews do nothing. Iam also leaking gas out the top of the plunger
Easy start when cold, hard start when hot, just barely catches after 3 or 4 times, then chugs along slowly almost stalling then gets up to 1500 idle.

On cold start idle does come down off of fast idle from 2000 to 1500

I don't see any obvious vac leaks

I don't know how to time with a light, I time by vacuum

Sometimes I wonder why we put so much wrench into our cars!

[XH29N0G]

I'm sorry I am not going to be able to solve the issue, but I have some thoughts that may help.  I am nowhere near as knowledgeable as some on here, but here are my two cents.

• First, I would get a timing light just to see where the engine is and also because it will let you see total advance. 
  
• Second, I found that timing by vacuum at idle gave me more timing than I expected (I think because of my cam).  The timing light helped because it made it clear to me that I would need to change the total advance to keep from pinging.
  
• Third, I see the notes in the MSD documents about using ported vacuum, and am also missing something with how the advance works.  My impression was that the vacuum advance would increase timing when vacuum was high.  So if one used manifold vacuum where it is high at idle and cruise (closed throttle blades) the timing would be advanced then and this might help, but at WOT and high RPM (where the mechanical advance is working) it wouldn't send the timing into the range where ping occurred.  From what I understand from the MSD document is that they want advance to come in during cruise (presumably when the the throttle blades are opened) and that is what the ported vacuum does.  I may be way off base with that.  See what other people say.
  
• Fourth, if you have gas coming out of the carburetor, I would find out quickly why that is the case.  A few years ago, I had my carburetor catch fire and had to put it out.  The excitement and ensuing clean up were enough to make me want to pay very close attention to that. 
  
• Fifth, it seems to me that you should be able to use the idle adjustment screws on the throttle blades (primary and secondary) to drop the idle enough to stall the car.  I wonder if you are able to adjust the primaries, but have the secondaries open, or if you have a vacuum leak with a fuel supply problem (fuel being supplied regardless of where the butterflies are set).  If you cannot stall the car with the idle adjustment screws, Can you stall the car by covering the venturis?

Good luck with it.

[frank1966]

Thanks for that detailed response. Iam very worried about the gas leak. I wonder if my stock fuel pump is too strong for edel carbs.

[frank1966]

Took off the carb today - it was soaked with gas on the bottom and the rear around the secondary's was filled with gas! I never saw such a flooded carb before and this is 2 days since i last started the car. I bet the original fuel pump is way over for edelbrock carbs, maybe the needle and seat has gunk or the floats are bad?

Yes i do not understand the MSD all in one as to why it calls for ported vacuum when most other distributors use manifold vacuum.

[XH29N0G]

Unfortunately, I do not know much about Edelbrock carburetors.  Maybe someone else will have an answer. 

I would think they should be able to accommodate the pressure from a stock fuel pump.  So I would think the reason you see all the gas is something else (like what you mention).  It also takes air to run at 1500 RPM.  So I would also want to rule out that you don't have two issues, one being extra gas from the carb, but the other being extra air.  I do not know if this would have to be a vacuum leak or if something like some of the throttle blades (primaries or secondaries) being slightly open could do it.

Regarding the distributor, I wonder if a call to MSD is in order.  I suppose they could set up how the vacuum pot works any way, or they could explain why.

[HPP]

If you set timing to max vac and then didn't back off a few degrees, you have too much timing. Even timing it by ear, you get the highest idle then back off a few. Figure out how to time it with a light and see where it is at.

For fuel, either your needle valve is hung open, has debris in it preventing it from closing or your floats are too high or both. I've used Ebrock carbs with very strong electric pumps and never had this overflow issue.

No experience with MSD all in one distributor, but I'd certainly call them.

If after fixing these issues, you still can't idle it down, try blocking off the power brake vacuum line. Occasionally brake diaphragms fail which causes a high idle via vacuum leak, no where near the engine.

[c00nhunterjoe]

Stock fuel pump is not your problem. If the carb is dumping fuel, the carb is the problem. Whether its debris or a faulty part, its in the carb

For the idle,are you sure the throttle cable is not preventing the linkage from closing all the way?

[frank1966]

Thanks, I finding TDC, making sure distributor is pointing at #1 on compression stroke. Pulled apart the carb, cleaned, air pressured, Float was 7/16, I did notice that one of the needle and seat covers were stuck closed, seemed pretty grimy down there.

[flyinlow]

A stock fuel pump ,like already mentioned should not flood your carb. Eddy carbs will have problems above 6-6.5 psi fuel pump pressure. (higher pressure aftermarket pump painted to match your engine?)

You might  disconnect the throttle and kick down linkage from the carb to verify that they are not holding the throttle open. Also check for vacuum leaks: PCV valve hose off or leaking, power brake hose, loose carb  mounting bolts.

Ported vacuum advance (what most Mopars came with from the factory) will increase the timing when the throttles are open above idle and the intake manifold vacuum is higher. (8-10 inches of vacuum or more) So it is advancing at cruise or part throttle acceleration . Not a WOT or idle.

Manifold vacuum advance is increasing the timing all the time except during engine starting and large throttle openings>

[frank1966]

Thanks, all links were disconnected, still high idle before i removed the carb. PCV and brake booster hoses were connected. Air breather valve on passenger side not connected. Connected to ported side of carb. The carb was pretty dirty, hopefully thats all it was, never saw so much gas on the underside of the carb. Plugs were black, strong gas smell, plugs were champion RJ14YC rather than RJ12? Not sure if that makes a difference, bought RJ12's. Still figuring out TDC on compression stroke, making sure distributor is pointing to #1 on compression stroke.

[AKcharger]

Frank may I strongly suggest you adjust timing. Timing has just as much to do with idle speed as the carb. if you have a light set it to 10° Before top dead center as a begining point. if you dont have a light move the distributor clock wise and counter clock wise to set idle at a reasonable level...THEN play with carb

[flyinlow]

Yea , set the timing first .

Take a picture of the top of your carb and post it. Straight from above with the engine idling ,warmed up.

The 12 number Champion plug is a colder heat range plug than a 14.

  Colder plugs are used in higher performance use engines . 383,0r 440 magnums came with j 11-y plugs ( kids driving Road Runners)

383 two barrels or 440 standard performance ( stationwagons, New Yorkers with old people driving them) came with j-14y.

If you drive around at low speeds (especially with a carb that's running rich) the colder j11-y or j12-y will foul easier. No damage done to the engine though, you will just get good at changing spark plugs and oil.

If you put j 14-y in your 440 Superbird and drive it on a Nascar track at wide open throttle the hotter heat range plug could over heat and cause pre ignition. This will damage your engine.