Very rough idle

[38plymouth]

I'm having a terrible time with my car right now. I rebuilt the carb last November and literally drove the car once and parked it. I also drained the fuel and replaced the fuel lines and put ethanol free fuel in it. The car wasnt running great and I parked it after a car show and havent driven it since. 

 

Im trying to get it running correctly and I got it running today and took it for a drive. It idled ok but wouldnt rev up very high and wouldnt go over 50. I took it home and pulled the carb and it was full of grey sludge, so was the clear fuel filter. I had to clean out everything on the carb. I put it back on the car and replaced the fuel filter. Now it idles terrible and the engine shakes and wants to die. When I rev it up it runs good. I pulled the carb and went thru it again and made sure every passage was clean. It didnt help. 

 

I put in new plugs, pulled the distributer and checked everything. No change.

 

What I do notice is fuel is squirting out of the accelerator pump holes at idle and I feel like that is the issue. I played with the float settings and that didn't help. What would cause this and also what are the symptoms of a high float and a low float?

 

I have a car show in 1 week and I dont want to miss it.

[knuckleharley]

40 minutes ago, 38plymouth said:

I'm having a terrible time with my car right now. I rebuilt the carb last November and literally drove the car once and parked it. I also drained the fuel and replaced the fuel lines and put ethanol free fuel in it. The car wasnt running great and I parked it after a car show and havent driven it since. 

 

Im trying to get it running correctly and I got it running today and took it for a drive. It idled ok but wouldnt rev up very high and wouldnt go over 50. I took it home and pulled the carb and it was full of grey sludge, so was the clear fuel filter. I had to clean out everything on the carb. I put it back on the car and replaced the fuel filter. Now it idles terrible and the engine shakes and wants to die. When I rev it up it runs good. I pulled the carb and went thru it again and made sure every passage was clean. It didnt help. 

 

I put in new plugs, pulled the distributer and checked everything. No change.

 

What I do notice is fuel is squirting out of the accelerator pump holes at idle and I feel like that is the issue. I played with the float settings and that didn't help. What would cause this and also what are the symptoms of a high float and a low float?

 

I have a car show in 1 week and I dont want to miss it.

Since you have to buy a rebuild kit to get a new accelerator pump,rebuild the carb using a kit designed to work with ethanol. Make sure any rubber gas lines or plastic fuel filters you have in the line are rated for use with ethanol,too.

[Tom Skinner]

Dump the gas in the tank. Fill Fresh with ethanol free fuel. Run it every day. These old Chrysler Cars do better while used - not sitting for long stretches.

Check to see if your flexible fuel line is mushy, mabye its eat up from all the crap gas (ethanol). I don't run crap gas in any of my vehicles.

Never any trouble with cleaning Carburators, Fuel Injectors, etc.,  because nothing in the Ethanol free gas to crap things up.

[38plymouth]

I already rebuilt the carb with and replaced all the lines and fuel. I have some type of an adjustment issue that i just cant figure out. It seems to be the accelerator pump. 

[Plymouthy Adams]

by design the accelerator pump only plays a part in transitioning from idle to run circuit....however one could easily have the balls reversed and therefore not shutting off the supply path when inactive or have trash on the seat or ball is not seating for other reasons easily corrected by a soft tap with a brass rod.....IF you have fuel in the carb throat, odds are it is seemingly coming from the accelerator pump when in fact it is discharging into the throat more than not due to a very high float level...rough idle would also be a side effect as the fuel will be way to rich a mixture.  As the fuel will be used in high speed you are experiencing a better running there but odds are if the vehicle comes to full operating temp it would show signs of over rich also but as a colder engine requires more fuel this is not immediately indicative as being a problem.    Suggest a close look at all four systems within the carb and proper setup....if using ethanol fuel on a regular basis, set float for a tad bit less fuel...odds of most folks running a flathead of out accelerating their fuel intake is slim here unless there is a fuel delivery problem also in conjunction with dirty or mistuned carb.

[38plymouth]

I actually lowered the float quite a bit and nothing changed. I am going to have to take the carb apart for the third time. I triple checked everything and it still dumps fuel out of the accelerator pump passages at idle.

[Plymouthy Adams]

30 minutes ago, 38plymouth said:

I actually lowered the float quite a bit and nothing changed. I am going to have to take the carb apart for the third time. I triple checked everything and it still dumps fuel out of the accelerator pump passages at idle.

you must now verify that the correct check balls are positioned and seat....

[Dodgeb4ya]

Was the tank re-sealed with tank sealer?

[Tom Skinner]

I had to rebuild mine three times before it was right also. It turnred out to be a ton of crud back up and in the back of the carb where the piston is controled by the passing button when you floor it. Once I cleaned all that out and replaced the Dash Pot Piston with a new one (As well as every thing that comes with the NAPA Kit it finally ran smooth. I don't rightfully know what to tell you but try try again?

[38plymouth]

I'm hoping to find some time to tear the carb apart again tomorrow. The only part I didn't take apart was the ball and clip under the accelerator pump. I did flood it with carb cleaner and hit it with air compressor. I'm really kind of at a loss about this right now. Hopefully cleaning that area solves the issue.

[Dodgeb4ya]

Did you remove the lower bowl plug and look into the emulsion tube area?

A hard area to check and clean unless you have the carter tool to remove the tube.

Edited October 28, 2018 by Dodgeb4ya

[38plymouth]

I think I found the problem, well at least I hope its the problem but I won't know for awhile because my battery is dead. Some moron left the key on for 2 day....

 

So anyway, I noticed that I used the base gasket on the top instead of the one on the bottom. I had one on it like the one on the bottom since last year but it tore when I pulled the carb the other day. So, I think thats it but wont know until the damn battery charges. 

[Los_Control]

Just a heads up, when leaving the key on, is possible to burn the points up. Just depends what position the points are in when you walk away.

Nothing to get excited about, just if it seems to have a spark issue you would want to look at them.

[38plymouth]

Well I got it running and I still have the same issue there is a ton of fuel dumping out the top where the power valve squirts it.I am at a loss I've had this thing apart 6 times and everything is clean and free no clogs no dirt no nothing I tried to call tech support at Mike's carburetor parts and they can't help me right now.. if anyone has any suggestions I'm all ears. I'm so frustrated right now.

[38plymouth]

A little more info after talking to mikes carb parts they had me turn the idle mixture screw all the way in while the engine was running. I did and it had no change. They believe that I either have a serious vacuum leak or a plugged idle passage. I tore the carb down again and ran wire into every place possible. I cant imagine that the carb could be any cleaner. That had a slight change and the mixture screw would barely cause the engine to stall after that. 

 

I also sprayed a half a can of carb cleaner all over any place that could have a vacuum leak and never found anything.  

 

I went thru the carb one more time and will try it again tomorrow morning. If that doesnt do it I need a new carb, I'm just frustrated beyond belief right now.

 

I also still dont know which base gasket is correct, I  think the bottom one since I do have a passage that looks like it needs vacuum.

[DJ194950]

Just use the one that has opening/s  that match the carb base And cover areas that do not.  There may be the one like lower one in your picture that may be the correct one to use iff you do not have one that matches perfectly as the kits are made to fit many different model Carter carbs with one general kit.

I have found the exact same issue with the gaskets on the kit for 1950 Plymouth carb I am working on currently. Same gasket mentioned above is what I am going to use as described.

 

Best of luck,

 

DJ

[Dennis Detweiler]

I had a similar problem with my rebuilt b&b carb. I messed with it for several days plus adjusted the float lower. No results. I replaced it with a rebuilt Stromberg and solved it.

[38plymouth]

5 hours ago, Dennis Detweiler said:

I had a similar problem with my rebuilt b&b carb. I messed with it for several days plus adjusted the float lower. No results. I replaced it with a rebuilt Stromberg and solved it.

 Can you tell me a model number and where you bought it?

[38plymouth]

I put the proper base gasket on this morning and still no change. I did notice the idle smoothed out a little when I sprayed carb cleaner on the throttle shaft. The idle mixture screw still doesn't do much but it will try to die when turned in. I did notice the engine dies if I plug this hole with my finger. Should this be open?

[nonstop]

Looking at other pictures, no. I am not too familiar with B&B carburetors, but that is below the filter and would be sucking in unfiltered air. Try plugging it and then tune it.

[38plymouth]

10 minutes ago, nonstop said:

Looking at other pictures, no. I am not too familiar with B&B carburetors, but that is below the filter and would be sucking in unfiltered air. Try plugging it and then tune it.

That hole has been open for the 25 years I have owned the car. Never noticed an issue with it though.

[Los_Control]

no idea what the hole is for, newer carbs do not have the holes, or at least mine does not.

[nonstop]

Is that the right carburetor for your application?  I ask because I was running the Stromberg WW that came on my car. Never could get the choke working just right and idle would fluctuate from time to time - BUT it ran. Further investigation showed it was set up for a gyromatic transmission and had an unmetered vacuum leak in the area of the air horn.  Replaced it with one set up for my powerflite and it runs like a champ.  It couldn’t hurt at least temporarily plugging the hole and trying to tune it.

[38plymouth]

If I put my finger over that whole it dies. Plus the whole has been open for at least 25 years. Mikes carburetor parts thinks I either have a massive vacuum leak or a low fuel pressure. I guess my next step is to pull the fuel pump out and completely drain and clean the tank. There is no sign of a serious vacuum leak.

[knuckleharley]

41 minutes ago, 38plymouth said:

If I put my finger over that whole it dies. Plus the whole has been open for at least 25 years. Mikes carburetor parts thinks I either have a massive vacuum leak or a low fuel pressure. I guess my next step is to pull the fuel pump out and completely drain and clean the tank. There is no sign of a serious vacuum leak.

Why not just put a fuel pressure gauge between the pump and the carb first to see if that is the problem? MUCH easier and quicker to do,and you know right away if you are at the root of the problem.