Very rough idle

[38plymouth]

13 minutes ago, knuckleharley said:

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.

Actually I am anning in doing that, I need to pick up some fittings. The fuel bowl is always fill when I pull the top off. I don't see how it can be a fuel issue or a vacuum leak.

[HotRodTractor]

1 hour 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.

 

I would venture to bet that hole is your massive vacuum leak.

 

What is the model number of the carb?

[nonstop]

You found the vacuum leak - that hole that makes the engine die when you plug it. I don’t know if it’s normally covered with the air cleaner or the rebuild knocked loose something that was blocking that hole, but that hole should not be open to unfiltered/unmetered air.

[38plymouth]

39 minutes ago, HotRodTractor said:

 

I would venture to bet that hole is your massive vacuum leak.

 

What is the model number of the carb?

C6J1, almost positive this hole has been open since i have the car. I have never removed anything from that spot and have rebuilt the carb several times over the last 25 years. 

[HotRodTractor]

12 minutes ago, 38plymouth said:

C6J1, almost positive this hole has been open since i have the car. I have never removed anything from that spot and have rebuilt the carb several times over the last 25 years. 

 

I was trying to find some info on that exact carb, but I am not finding  anything helpful except: http://www.carburetor-parts.com/assets/manuals/carter_bb_1937_prior_manual.pdf That document at least tells you to use the gasket with 4 slots if you don't have a governor.

[HotRodTractor]

15 minutes ago, 38plymouth said:

C6J1, almost positive this hole has been open since i have the car. I have never removed anything from that spot and have rebuilt the carb several times over the last 25 years. 

 

I have never seen a carburetor that pulls air from a source other than its main throat. Not saying you are wrong - but I'm not inclined to believe you are correct. Perhaps something was in there and fell out between the last time you drove it and your current issues?? Would a gasket change perhaps uncover a hole that wasn't open before? If you plug it - can you then tune your engine?

[Jerry B]

Vacuum leak at throttle shaft will make it difficult to adjust ideal.

[kencombs]

I'll bet that hole had a welch plug in it at one time.  Try this:  plug the hole with tape.  turn the idle speed screw in far enough to provide adequate air for idle.  Now set the mixture screw.  The speed will need changing after that and also the mixture after the last speed setting .

 

costs nothing and will tell us a lot.

 

 

[38plymouth]

I found it. Thank God now I can sleep tonight. We have been out of town all day at a food show and this has just been driving me crazy as soon as we got home I was right back at it and tore the carb down one more time. I was determined to make sure every orifice was spotless. This time I noticed the idle orifice tube seemed to be slightly plugged. I had to use a very small sewing needle to punch through it then it cleaned right up with carb cleaner.

I put the carb back on crossed my fingers and it started up and idled beautiful. I do still have a slight leak at the throttle shaft but I can live with it for now.

 

The next couple days I get to drain the old fuel and clean the tank with something and get new ethanol free fuel in it. 

 

Thank you all. Oh and it appears the hole is supposed to be open. The car simply will not run with it plugged. I sent a picture to Mikes carburetor parts get his opinion so maybe I'll hear back tomorrow. But she's running great now.

[Dodgeb4ya]

In the Carter parts and service book that hole looka to be open... no bolock off plug shown.

[38plymouth]

Sometimes you just have to wonder what you have done to anger the car gods.

After finding the plugged orifice in my carburetor last night it wouls finally idle good. I didn't want to leave it running long because I still had one year old gas and some grey goo in the fuel. This morning I drained all the old fuel and then put in a gallon of lacquer thinner and shook the hell out of the car a bunch of times. I then drained that and everything was nice and clean. I filled it with fresh non-ethanol gas and the fuel pump wouldn't pump the fuel. I pulled the fuel pump and it was filled with grey goo. I cleaned that all up nice and primed it with fuel and got the car running again.

It was running good for a minute and then started idling rough again and I figured something plugged from a bit of old fuel. I tore the carb down again and put it back together got it running again and now fuel is pouring out of the throttle shaft. At this point the carburetor is stripped down for the 12th time and is soaking in lacquer thinner until tomorrow. If that doesn't work I'm buying a new carburetor.

Looks like I might miss the car show Saturday. I love old cars.

[DJ194950]

Sounds like it is time clean fuel line tank to pump  with Low pressure - put air to the gas tank opening to pressurize clearing the lines while catching any fuel in a disposable can.

Do this without the forward inline fuel filter inline if any. If there is not a filter just Before the pump-add one after this cleaning out!

 

Seems you still have some old Jello left in the fuel system.

 

No more carb. cleaning- -I wish for you!

 

DJ

[38plymouth]

1 minute ago, DJ194950 said:

Sounds like it is time clean fuel line tank to pump  with Low pressure - put air to the gas tank opening to pressurize clearing the lines while catching any fuel in a disposable can.

Do this without the forward inline fuel filter inline if any. If there is not a filter just Before the pump-add one after this cleaning out!

 

Seems you still have some old Jello left in the fuel system.

 

No more carb. cleaning- -I wish for you!

 

DJ

 

I did that and got nothing dirty from the line. The tank was pretty clean too. The grey goo was only in the fuel pump, filter and carb. Now I think its running rich, I have black smoke coming from the exhaust and fuel dripping from the throttle shaft. Never had that issue before.

[Plymouthy Adams]

you will need be over filling the bowl for the fuel to get to the point to flow down the venturi wall and out the shaft.....I thought this was asked but do not recall if answered, but has the tank been sealed in the past?  

[38plymouth]

9 minutes ago, Plymouthy Adams said:

you will need be over filling the bowl for the fuel to get to the point to flow down the venturi wall and out the shaft.....I thought this was asked but do not recall if answered, but has the tank been sealed in the past?  

 

I havent done it in the 25 years i have owned it. Its an original low mileage car so i doubt it. Its definitely flooding at idle and i just dont have time to work on it anymore tonight. Back at it tomorrow morning. 

[Plymouthy Adams]

thanks for answering...….I have seen so many that have been sealed in the slowly leach the product through the fuel system over time.  This apparently will not be a problem for to worry over.   

[knuckleharley]

2 hours ago, 38plymouth said:

Sometimes you just have to wonder what you have done to anger the car gods.

After finding the plugged orifice in my carburetor last night it wouls finally idle good. I didn't want to leave it running long because I still had one year old gas and some grey goo in the fuel. This morning I drained all the old fuel and then put in a gallon of lacquer thinner and shook the hell out of the car a bunch of times. I then drained that and everything was nice and clean. I filled it with fresh non-ethanol gas and the fuel pump wouldn't pump the fuel. I pulled the fuel pump and it was filled with grey goo. I cleaned that all up nice and primed it with fuel and got the car running again.

It was running good for a minute and then started idling rough again and I figured something plugged from a bit of old fuel. I tore the carb down again and put it back together got it running again and now fuel is pouring out of the throttle shaft. At this point the carburetor is stripped down for the 12th time and is soaking in lacquer thinner until tomorrow. If that doesn't work I'm buying a new carburetor.

Looks like I might miss the car show Saturday. I love old cars.

Seems to me like this "gray goo" just might be old gas tank sealer gone bad,or done improperly. I guess if you have the patience of a saint you can pull the tank,have it cleaned and boiled out,and then recoat it and hope the coating works better this time.

Or you could spend 230 or so bucks for a brand new gas tank that is galvanized inside and has no rust or trash,and spend more time driving than cleaning gas tanks.

[Dodgeb4ya]

2 hours ago, 38plymouth said:

Sometimes you just have to wonder what you have done to anger the car gods.

After finding the plugged orifice in my carburetor last night it wouls finally idle good. I didn't want to leave it running long because I still had one year old gas and some grey goo in the fuel. This morning I drained all the old fuel and then put in a gallon of lacquer thinner and shook the hell out of the car a bunch of times. I then drained that and everything was nice and clean. I filled it with fresh non-ethanol gas and the fuel pump wouldn't pump the fuel. I pulled the fuel pump and it was filled with grey goo. I cleaned that all up nice and primed it with fuel and got the car running again.

It was running good for a minute and then started idling rough again and I figured something plugged from a bit of old fuel. I tore the carb down again and put it back together got it running again and now fuel is pouring out of the throttle shaft. At this point the carburetor is stripped down for the 12th time and is soaking in lacquer thinner until tomorrow. If that doesn't work I'm buying a new carburetor.

Looks like I might miss the car show Saturday. I love old cars.

Don't buy a new carburetor till you confirm whats contaminating the fuel line and pump... and now you might find a tiny flake holding the needle off the seat in the carb if thew carb  is flooding .

If your tank is lined I would crush it and throw it away and buy a new tank.

[Los_Control]

Last year I rebuilt a holley 2barrel on my uncles 70 something dodge pickup. It was filled & plugged with grey goo. I really think it was from old gas.

Seems like the last few years they made some of the gas restrictions tighter, now the gas is less stable and I think the goo is a by product.

 

If it is the same goo I saw, it is not from a tank liner or anything else, simply old gas that technically is not old enough to be called old yet.

 

As I remember, it was almost the consistency of oil and water, just real sticky, and the color of gray jb weld. Real ugly stuff, never seen it before.

Edited November 1, 2018 by Los_Control

[38plymouth]

1 hour ago, Los_Control said:

Last year I rebuilt a holley 2barrel on my uncles 70 something dodge pickup. It was filled & plugged with grey goo. I really think it was from old gas.

Seems like the last few years they made some of the gas restrictions tighter, now the gas is less stable and I think the goo is a by product.

 

If it is the same goo I saw, it is not from a tank liner or anything else, simply old gas that technically is not old enough to be called old yet.

 

As I remember, it was almost the consistency of oil and water, just real sticky, and the color of gray jb weld. Real ugly stuff, never seen it before.

 

That is exactly what im dealing with. 

[9 foot box]

   Hopefully, the last bit of goo in the line was holding the inlet open and the float couldn't shut off. Maybe St.Christopher has carbs in his travel plan. Here's to a better tomorrow.

[38plymouth]

10 hours ago, 9 foot box said:

   Hopefully, the last bit of goo in the line was holding the inlet open and the float couldn't shut off. Maybe St.Christopher has carbs in his travel plan. Here's to a better tomorrow.

 

 

That was it. I carefully reassembled the carb this morning and didn't find anything wrong until I took a look inside the seat for the needle. There was a little piece of trash stuck in there. I'm happy to say she's running great now. I just returned from a test drive. Actually I can't remember it ever running better. I used to have to keep the choke half closed in order for it to run well, not anymore!

[9 foot box]

   I saw earlier today, that things were humming again. Put a fuel filter before the pump, there is more scum in the line. I think when the lines dry up with ethanol, it leaves a residue. And additives will clean the system eventually. You don't want to go through this again.