LONG post, sorry.

1979 B200 Van 318 2V, AT, PS 55K original miles.

OK, last year this started:

Run the van to a standard point in town and back, maybe 8-10 miles, 45 mph.
On the way back, almost home, it starts to stumble and run rough, like the choke (remember those) was stuck closed. But the choke is fine.

So then I run it with the cover and air cleaner off, and when it gets to that same approximate run time, the carb starts flooding. You look into the carb and you can see the gas flowing into the engine, so much so that it seeps out the bottom of the carb around the gasket.

So I tell this to the mechanic and leave it there, He rebuilds the carb. It seems to run ok, idle a little high but I dont really take it any place far to test it.

So, thinking it's cool, I take it to have fenders put on. The body guy has it sitting around for a year and finally it's done, but the carb is screwed up he says. I get it started and it runs fast, but as soon as I step on the gas it dies-I assume the choke is not working.

I get it home, and can't work on it cause it's a freaking awful winter and I have a tarp on it because I have a rain leak some where.

So this spring I try to start it, no dice. Pull the engine cover and find the body guy has safety wired the choke open, because he (probably) thinks the choke wont open-he was having trouble moving it around the yard.

Remove the wire, find idle is set way high. So I get a tach and get it close to where it should be...I am amazed this seems to run so well. I drive it around the block a couple of times, everything 's great.

Next day, since I don't believe in miracles, I take it on the "standard" test route. It's ok!, So I decide to do the loop again, this time, as I get back it stalls, suspect the old gas flood problem again.

I wait about 15 min. and I get it started, running for **** and stalling several times I get it to the parking space. When it starts it makes a lot of black smoke. I have to blip it to keep it running.

OK, back in parking spot. Pull engine cover, start, get it running, and it is acting like there is too much gas. Shut it off and look into carb and can see the gas coming in, not from the accelerator nozzles but from whatever source below that is. I can see wet gas running onto the throttle plate. Shut it off and can STILL see wet gas running on to plate at least for a while.

OK. So now you know what it does, before I talk to the mechanic who rebuilt the carb, what could it possibly be? And why does it run great for the first 10 or 12 miles or so. It's mechanical pump, so it's unlikely to be overcoming the floats with pressure and it continues to put gas into the carb for a while after it dies from flooding. It's not hot enough outside, it does this in winter too, to boil fuel and besides it does it with the cover and air cleaner off too.

Any clues.

PS it's a Carter and the numbers on it are 0-2681

 

Ever change the fuel filter or fuel pump throughout this flooding issue?

 

Incorrectly rebuilt or warped casting (it happens). Carter is generally a solid & reliable carb but castings can warp with time and heat. Either identify the issue and address it or replace the carburetor with a decent rebuilt.

 

Next time its doing it, smack the carb with a hard object.
Like a wrench, small hammer, big screwdriver handle.
Im thinking your float is sticking or the valve is gummed up.
Either way its not shutting fuel flow off into the bowl and its overflowing.
A good whack should smarten it up.
Try a fuel additive. I really like Sea Foam.
Works fast.

 

how it looks like, there is a gasket not mounted right from the floater chamber.
you should also check the acceleration pump, which is a membrane pump activated when you step on the gas. if it is broken or ripped, the gas is jusst running trough.
but i would not hit with anything on the carburator- it will not help.
how you describe, your vehicle is sitting for a long time. this might be the problem.
Especially the E10-E15 Gasoline clogges up your vents inside the carburator. you might have to clean it again.

taking a carburator apart is not too hard.
get you a clean table, put a white bed sheet on it and start taking it apart- if you don't know- make pictures with your phone from every step.
important is, that the floater has no leak and there is no gasoline inside.
all jets need to be clean- air pressure would be great to blow it out.
when you have the carburator apart, put it in a ultra sonic bath- they are cheap- somewhat around $100.00. if you work on old cars or motorcycles- you will need them all the time once you have one.
leave the parts (not the gaskets and rubber seals) over night in the bath. in the morning take it out and blow everything out with air.
get you also a new gasket set, where every gasket from the carburator is in and replace all.
then put everything piece by piece together.
A lot of times the carburators are not adjusted right. important is the basic adjustment.
when you have everything together, turn the air-screw completely in and then 1 1/2 turn out. the same with the gas screw.
for a correct adjustment you will need a Co-tester anyway. you might have to find a shop who knows what it is, has one and know now to read it.
if you Van has Catalytic converter, check the Co in front. should be somewhere around 1.5-2% if you can't find the correct Co% somewhere in a manual.
and that combined with the correct rpm.
believe me- you can do it- and if you once done it, you will ask yourself why you paid people to do it. Carburators are plane mechanical simple pieces of metal. that's it.
If you make your pictures from every step, you can't do nothing wrong.

if it still occurs, I admit- there is a problem with the carburator by it self and you should replace it. what that cost is worth the try to fix it by your self.

A tip if your vehicle sits for a longer amount of time:
when you know, you have it sitting for longer time (example over the winter) make your tank full- if possible ethanol free gas.
pull the fuel supply line off the carburator and start the engine. let it run till it shuts off by it self. plug the fuel line back up.
this prevents your carburator from clogging up through old gasoline which will not fire good anyway after a while. Also a full tank prevents water in the tank through moister.
dependig how long you have the vehicle sitting there- if it's longer than a half a year, you should pump the tank out and put fresh gasoline in.
the old you can use in your lawnmower.

Chris

 

Especially the E10-E15 Gasoline clogges up your vents inside the carburator. you might have to clean it again.

I VOTE FOR CLOGGED VENT...
I had an old carburated V-4 boat engine with twin carbs... sat for a number of years. When I started it, it ran, but only until it warmed up, then too much fuel, no power, so much fuel that it ran out of the carb overflow tube and created a slick on the water. I had rebuilt and cleaned the carbs several times, thinking it was a float issue. Finally the fourth time, took carbs apart again, going crazy with the carb spray cleaner, I finally noticed a vent at the top of the fuel bowl was clogged with MUD... very hard to see it the first several times I had the fuel bowl open... some damn insect built a nest in the fuel bowl vent... being clogged it did not allow air to escape the fuel bowl, thereby keeping the float from never getting high enough to shut off the fuel flow. The vent hole was about 1/16 inch in diameter.

Stored engines outside are great places for insects to live! Carbs are not rocket science... take yours apart and poke every orifice with a strong stream of BRAKE Cleaner, then finish off with carb cleaner. On mine the wet mud looked silver, like the carb, which is why it took me four times to even see the damn vent hole...

good luck

 

1st check your oil and make sure you don't have it over filled with fuel that has leaked into the crankcase.
Check your fuel lines for degrading and continually fouling the carb needle and seat. New lines and an inline filter may help. Also, the float may have lost buoyancy and is not providing enough force to overcome pump pressure.

 

Changed the fuel filter 25 miles ago cause the body shop guy said it must be dirty. We cut the old one open. It was fine.

I did change the fuel pump several years ago when I had a different problem (note this is probably only 1k mi)...the truck was shutting off cause it would not draw fuel from the tank. Putting new lines from the tank forward to filter fixed this. After I eliminated the shutting off problem I discovered this problem, which only happens after you drive a few mi. as I said.

Is it possible for a mechanical pump to put out so much pressure that It overpowers the floats?

there is no non ethanol gass within 3 or 4 states from here.

 

Lol. I meant TAP it. Not beat it till you break it.
Sometimes a light tap can dislodge a stuck float.
Never hurts to try and find an issue.

 

the fuel pump- mechanical or electrical- always pumps more than needed. one reason is, to supply always enough fuel, second to keep air out and third to keep the fuel pressure up on a certain level. the fuel which is not needed flows pressureless back to the fuel tank.
there is the possibility that the return line is clogged up.
It also can be clogged up inside the carburator.
you can test it, when your engine is running and you pull the return line off at the fuel tank and see what's coming. if it's just a little bit and thin, there is something wrong.
but this issue is very rare- but not impossible- especially on a old vehicle.
do you have metal fuel lines (don't know that)?
if so, blow them out with air pressure. Rubber lines dissolve over the years and it's possible that they getting greasy inside and clogg up.
due to your description- this is all we know- I would not see a problem there. I guess you will not get around to remove the carburator and take it apart and clean it. maybe the tech who did it before did something wrong? nobody is without fail.
if you really don't want to take it apart- or don't know anybody who can help you, and also show you for the future, how to do it- as I said- you don't need whichcraft to do it- what about getting a used one from the junk yard and install it and see if it works?

If you want to take it apart- one possibility is to buy a dyno jet kit which also inproves the performance.