Flooding Carb on Idle

[66Sprinter]

Hi,

I got my new engine started and it runs great. I have the timing at 12deg @ 1000-1200rpms.

I have enough time on the cam so its broke in. No problems with plug wires and vacuum. Using DUI and plugs gapped at .055" I have an adaptor from 1.5" to 1.75" bore. Looks great..but!!

As I start to lower the idle on my 1101...when I get lower to around 1000rpms there is enough vibration (from the cam) to shake the engine. I think the needle is getting stuck open. When I get to 1000rpms...the carb will flood and stall. Gas comes out the top.

Restart and go through it all and it runs great..so long as I am over 1200rpms. When I bring it down..samething happens. Do I need a new carb..maybe larger?

I wont get back home till Sunday.

Jim

 

[pedal2themetal45]

If you talking about the needle in the needle and seat at the fuel intrance to the carb... that has nothing to do with the vacuum or idle of the motor.... the float holds prusher against the needle to shut off the fuel... if its flooding out the overflow your float is set to high... or you have tomuch fuel prusher..
Tim

 

[jamyers]

As I start to lower the idle on my 1101...when I get lower to around 1000rpms there is enough vibration (from the cam) to shake the engine.
...

I wouldn't think a 268 cam would shake *that* much, sounds like your float is either too high to begin with, or you've got some trash in the needle valve, or there's something else going on as well. ANYTHING in the needle valve can cause problems, even a tiny crease/crack in the needle seat, and at a high idle it may be using anough fuel to stay ahead of the leaking seat. I'd take the carb off and make sure it's clean, especially the fuel inlet and idle passages.

I'll also bet that at 1000 rpm you've got some centrifugal advance coming in, which will go away as the revs drop, so your initial advance is actually less than 12 degrees. Shouldn't make that big a difference, though. Just something to think about.

 

[JackFish]

Perhaps if you back the timing off to, say 8 or 10 degrees, it might help lower the revs enough to sort out the carb.

 

[mach1 mark]

Jammer, how does it act when you put it in drive?

 

[66Sprinter]

Well the idle is about 1200....so she is already cooking.

I dont need to add gas when I am feathering the clutch. Into first is a real experience. I have reduced my treadwear some on the back tires.

Shifting from gear up and down..will give me some jump..

Other than that i am good all the way through 4000!

 

[mach1 mark]

Thats great!! 8)

 

[66Sprinter]

OK...I am stuck in Dallas until the holiday. (Darn work..always gets in the way)

So I called some folks and discussed items from the forum (thanks guys!) and asked some questions. Plugs are good, wires right, dizzy OK, vacuum leaks NONE and plenty of gas PSI to the carb.

I did call Pony carbs and when I described the problem, the tech asked me to send a picture of the carb to him. He called back and said that the carb is an 1100/1 only without power module. He said there is not enough air getting through due to performance mods and headers. He said he could rebuild the carb adding about 30-50cfm, replacing venturi's, jet, and a performance rebuild using engine specs.

So ............I have a 1.75" carb opening on the manifold...isnt there a carb that is a direct fit??? What about a two barrel? Little skeptic at this point. I dont doubt his experience, but it what he said is true..why not go larger carb then rebuild that one???

Open for opinions on this.

 

[jamyers]

...He said there is not enough air getting through due to performance mods and headers.
...

Not enough air at IDLE is causing your trouble??? I'm skeptical too.

I still think your float height is too high or there's some trash in the needle valve (or maybe too much fuel psi if you've got a performance pump?)

 

[66Sprinter]

The fuel pressure is about 5-6psi...so I am not too worried, although it is a new fuel pump.

I am balancing the rebuild at Pony (w/performance) vs a 2bbl like a Autolite 2100, holley 350 or even a Demon 350..(Langdon Stovebolt sells an adapter!)

The tech seemed to ID the problem when he asked me about the changes in engine from stock...so I am just sitting on this for the rest of the weekend. I have no chance to get back home until TDay.

 

[Bort62]

What he said doesn't make any sense. Sounds like snake oil.

 

[pedal2themetal45]

READJUST THE FLOAT....
That guy at poniy's is druged up ... not getting enough air thats stupid..
IF THE GAS IS COMMING OUT THE OVER FLOW AND FLOODING THE CARB THE FLOAT IS TO HIGH................


A HEADER HAS NOTHING TO DO WITH THE CARB GETTING AIR.
DON'T LISTEN TO THAT BOZO AT PONY....

1200 RPM'S IS WAY FAST FOR AN IDLE... IDLE SHOULD BE AROUND 700 TO 750 ......
Check you float level... Take the top off the carb turn it upside down.. the part of the float that is closes to the top the the carb should be setting at least level with the top of the carb. or pointed upward a little (away from the top of the carb..not towards it..)

You came here for advice PLEASE try our advice be for you thro $$ away on a bigger carb...
how did you check for vacuum leaks??
Tim

 

[ludwig]

IDLE SHOULD BE AROUND 700 TO 750 ......

... in Drive.

how did you check for vacuum leaks??

All you need to do is check for vacuum leaks.
You know how to check for vacuum leaks don't you?
Just pucker up and ...

 

[66Sprinter]

I used the old cigarette smoke trick all up and down the hoses to and from the dizzy and brake booster. Nothing sucking?

As for the symptom...I can't get the idle lower than 1000-1200. When I turn down the idle screw..at about 1000 rpms..the carb will flood and gas gushes out the top! Ponyman says that I am sucking more gas then air and thats why I am getting the "old faithful" symptom.

I want to set the idle at 800...so I can dial in the dizzy to 12deg..although i am about there yet.

I am not home now..so I have to wait until the day after thanksgiving to get back to the car. I will have my son and friends look in on some things for me while I am still in Dallas. I am not firm on anything yet. I will have them check the float or do it myself on Friday.

I do respect all the advice and I am not blowing any of it off. But a 2bbl upgrade is used on alot of hot builds so far..so it seemed logical that maybe it would fit my situation, rather than rebuild the carb to add more CFM. I wonder what the performance difference would be, now with the new engine!

Thanks again for all the help and suggestions. Cold beer and fried turkey at my house for all that can make it!

 

[JackFish]

Check the needle (inlet) valve, maybe it's stuck open.

 

[ludwig]

Use a vacuum gauge too. Tweak the dizzy until you pull a minimum 18 pounds. That will get you in the neighborhood.

Personally, I think is the float.

 

[66Sprinter]

I sent an em to my son. He will get a vacuum gage from a parts store and we can check it when I get back on Friday.

I would like to hear from those who have 2bbls and how do they run.

 

[jamyers]

I had a Holley / Weber 2-bbl on my stock 200, then switched to an Autolite 1100. Apart from the progressive throttle, I can't tell much difference, anthough I'd say that the 2-bbl was a tad faster.

Stock 200 with Duraspark and HEI ignition, all else stock.


(and the guy at ponycarbs doesn't know what he's talking about. Sucking too much gas and not enough air - at IDLE???) :roll:

 

[woodbutcher]

Don`t know what that guy at Pony is smoking.HOWEVER,I`ll take a bale.
Leo

 

[66Sprinter]

My son says we have 16-20 vacuum with gage. He is taking the carb off and will get a rebuild kit. I asked him to diss-assemble the carb and let it soak till I get home.