B&B Carb Diagnosing

[55 Fargo]

Hi all, just went out to start engine, it went 2nd hit of starter button after 16 hours in cool garage 30 f inside.

This is a lot better than before, since the install of a new coil/battery cables.

But my carb is wet where the fuel line area is, not the line or fitting, but the top gasket area on the carb.

I notice this everytime I cold start the engine.

Is this indicative of the float allowing gas to be pumped in, even though it may be full?

I also experience a lot of fuel boil in summer, I have my fuel filter mounted down below the manifolds close to the inner fender, it as far away from the manifolds as possible. Is this a bad location for a fuel filter, as it should not be underhood I have read as the heat will cause more problems with a filter than just a fuel line.

Here are a few pics of my fuel line and filter...........Fred

[Normspeed]

Fred, I've been battling leaks and flooding on my B&B carbs forever, and they can be frustrating. Here are my thoughts, and I hope to learn from some of the other members too, especially on the source of internal leaks.

First, the float may just be set too high. Very easy to correct. I have mine set a lot lower than the recommended level and it seems to still run well. If the book says 5/64, mine are set at 3/16" (12/64). You might try 7/64 for a start. Unless you're in a real hilly area, the low float shouldn't cause driveability problems.

Second, you may need a fresh float needle and seat. You can inspect the needle tip with a magnifier to see if it's getting worn. A carb kit will have a new one.

You could possibly have a leaky float. While yours is out, hold it near your ear and shake it. If there is gas inside you'll hear it.

The area right near the fuel inlet, the top piece of the carb sometimes warps. Take it off and place it on a piece of medium wet or dry sandpaper on a very flat surface, and slide it over the paper until you can see that the surface is "planed" flat. When it's done it will be shiny metal all around the gasket perimeter.

Also, there should be a horse shoe clip over the float retainer pin. Some of these from rebuild kits are too large or not seated properly, and they will hold that top piece off the gasket and can help warp the piece. Check that out.

Last, if your gasket is compressed from use, buy a kit for fresh gaskets, or, buy a tube of Hylomar blue sealant. Spread a thin layer on both sides of that top gasket before reassembly. Hylomar blue is fuel proof and non hardening. Great stuff.

Heat is a problem. Try to route your lines and filter as far from the exhaust as you can. Try some insulating material, either store bought or home made, on the lines, and install a shield between mechanical pump and lines. I installed this expensive and ugly stuff called FireShield on mine from a race boat supplier.

With the help of forum member James Curl, I've found a source for insulating spacers and gaskets that go under the carb. I'm awaiting delivery on those and I think they will help with the boiling gas problem. Warning, these are Chevy parts:D. Also, with a stock air filter you could create a hood clearance problem with these.

I'm about to install a fuel block, fuel pressure regulator and flexible lines, routed over the head instead of near the exhaust. That might help mine, where I think excess pressure from the electric fuel pump might be a contributing factor.

That's all I know. I'll admit, with all this, I still get an occasional hot restart problem with the raw gas fumes and long cranking time. If I win the lotto, I'm going to find two brand new B&B carbs for mine, I'll bet that solves it for good!

PS your exhaust manifold looks great.

[randroid]

Fred,

It shouldn't matter where the filter is located as long as you have ample fuel flow to the pump. Come to think of it, it shouldn't matter where the filter is located even if you don't have ample fuel flow to the pump because in such a case you're not going to ... oh, never mind. Anyway, I belong to an air-cooled VW forum and the general thought there is that, because of the inherent fire dangerwith those engines, anywhere other than in the engine compartment is a better place for the filter. I have mine at the transaxle, but some of the guys mount theirs right at the tank. Your filter should not cause any problems where it is.

-Randy

[55 Fargo]

Fred, I've been battling leaks and flooding on my B&B carbs forever, and they can be frustrating. Here are my thoughts, and I hope to learn from some of the other members too, especially on the source of internal leaks.

First, the float may just be set too high. Very easy to correct. I have mine set a lot lower than the recommended level and it seems to still run well. If the book says 5/64, mine are set at 3/16" (12/64). You might try 7/64 for a start. Unless you're in a real hilly area, the low float shouldn't cause driveability problems.

Second, you may need a fresh float needle and seat. You can inspect the needle tip with a magnifier to see if it's getting worn. A carb kit will have a new one.

You could possibly have a leaky float. While yours is out, hold it near your ear and shake it. If there is gas inside you'll hear it.

The area right near the fuel inlet, the top piece of the carb sometimes warps. Take it off and place it on a piece of medium wet or dry sandpaper on a very flat surface, and slide it over the paper until you can see that the surface is "planed" flat. When it's done it will be shiny metal all around the gasket perimeter.

Also, there should be a horse shoe clip over the float retainer pin. Some of these from rebuild kits are too large or not seated properly, and they will hold that top piece off the gasket and can help warp the piece. Check that out.

Last, if your gasket is compressed from use, buy a kit for fresh gaskets, or, buy a tube of Hylomar blue sealant. Spread a thin layer on both sides of that top gasket before reassembly. Hylomar blue is fuel proof and non hardening. Great stuff.

Heat is a problem. Try to route your lines and filter as far from the exhaust as you can. Try some insulating material, either store bought or home made, on the lines, and install a shield between mechanical pump and lines. I installed this expensive and ugly stuff called FireShield on mine from a race boat supplier.

With the help of forum member James Curl, I've found a source for insulating spacers and gaskets that go under the carb. I'm awaiting delivery on those and I think they will help with the boiling gas problem. Warning, these are Chevy parts:D. Also, with a stock air filter you could create a hood clearance problem with these.

I'm about to install a fuel block, fuel pressure regulator and flexible lines, routed over the head instead of near the exhaust. That might help mine, where I think excess pressure from the electric fuel pump might be a contributing factor.

That's all I know. I'll admit, with all this, I still get an occasional hot restart problem with the raw gas fumes and long cranking time. If I win the lotto, I'm going to find two brand new B&B carbs for mine, I'll bet that solves it for good!

PS your exhaust manifold looks great.

Normspeed, just got off the phone with one of about 5 carbshops in Winnipeg, the guy I spoke to is a 1 man shop.

He stated my carb symptoms are as he said"typical of old carbs".

His shop price $100.00 roughly to rebuild carb again, he sated he can get rid of any leaks, by truing the carb surfaces.

So 100 bucks ain't bad, might take carb in soon, as I just love to keep spending a hundred here a hundred there, beofre you know it you spent 10 grand.

I have got about $3000.00 into my car already, and there is a lot more to go. I suppose this is a better than drinking,gambling, womanizing and smoking, oh yah golf and fishing.

I would someday like to rebuild my 251 engine, then go with dualcarbs/exhaust, disc brake cnversion, and maybe a T5 trans, my ultimate goal. Some guys figure I sould go modern V8 and auto trans, not my idea of fun..........Fred

[Young Ed]

Fred you should be able to handle the carb yourself. They aren't that complicated.

[greg g]

Fred the carter is one of the easiest carbs there is to rebuild. As far as truing the surfaces, that can be accomplished by placing a piece of fine sand paper on a flat surface, piece of glass works great, and making a few strokes of the airhorn (top piece of the carb) over the paper. Carb kits are about 20 to 30 buck. I sure you can find a better use for the other 70 bucks than buying steak dinners for the shopguy. Getting it off the car is probably the hardest part.

[Young Ed]

Fred I trued mine up with the old cutting board from the kitchen(don't reccomend using the current kitchen one) You wouldn't even have to remove the entire carb if you didn't want to. You could just remove the air cleaner and then the top of the carb.

[55 Fargo]

Fred I trued mine up with the old cutting board from the kitchen(don't reccomend using the current kitchen one) You wouldn't even have to remove the entire carb if you didn't want to. You could just remove the air cleaner and then the top of the carb.

Sounds like a good idea Ed and Greg, I have spare gaskets from the last kit.

I had a guy at work in the maintenance garage rebuild this carb in the winter of 2006.

he soaked it in cleaner, used a new NAPA carb kit, all check out well, he used the method to tru the surfaces as we have described.

So maybe your right Ed, just take off the top of the carb, check float, tru surface, and maybe use doubles gaskets on top of carb.

I have a spare ball and ball right in fron of me, yes there quite simple carbs.........Fred

[greg g]

There should be a fibre washer were the fitting from the fuel line attaches to the float bowl casting, they are also commom source of weeping leaks. To lower the float grab the tang that closes the needle and bend it toward the front of the car with needle nose pliers. I run mine lower than factory spec also. Keeps the summer heat sink hot start problems to a minimum.

If your carb was rebuilt such a short time ago, I would just lower the float and snug all the screws up.

[55 Fargo]

There should be a fibre washer were the fitting from the fuel line attaches to the float bowl casting, they are also commom source of weeping leaks. To lower the float grab the tang that closes the needle and bend it toward the front of the car with needle nose pliers. I run mine lower than factory spec also. Keeps the summer heat sink hot start problems to a minimum.

If your carb was rebuilt such a short time ago, I would just lower the float and snug all the screws up.

Thanx Greg, will try this first, then see what happens.

Can hardly wait till someday when I have 2 of these going at the same time. Or maybe I should try and set-up a 2 bbl Holley instead with headers or split exhaust.

Has anyone tried the 2 bbl Holley route on a Mopar Flathead?

[Young Ed]

Fred I've got a 2bbl stromberg that was OEM on 55-56(or was it 56-57) flatheads. Planning on running it on my next old truck project.

[55 Fargo]

Fred the carter is one of the easiest carbs there is to rebuild. As far as truing the surfaces, that can be accomplished by placing a piece of fine sand paper on a flat surface, piece of glass works great, and making a few strokes of the airhorn (top piece of the carb) over the paper. Carb kits are about 20 to 30 buck. I sure you can find a better use for the other 70 bucks than buying steak dinners for the shopguy. Getting it off the car is probably the hardest part.

Hi Greg, your right about the simplicity of these carbs, just had a spare ball and ball carb apart and back together again in a very short time. Not a whole lot to em............Fred

[55 Fargo]

Fred I've got a 2bbl stromberg that was OEM on 55-56(or was it 56-57) flatheads. Planning on running it on my next old truck project.

Is the carb base the same as for the b and b carbs or is a different intake all together.

[Young Ed]

Its a 2bbl intake. The carb base is 4 bolts.

[Fluid drive]

Lots of good ideas and hints !

One of the old time tricks that will aleviate many headaches is the installation of a"bypass" on your fuel pump. Please excuse me if someone else posted this idea!!!

You need two tees , one for the outlet side and one for the inlet side of your fuel pump . they should be fuel line size x 1/8 compression. Next take a piece of 1/8 copper line long enough to go between them and solder one end almost shut-I use a piece of aluminum wire about the size of a straight pin to make a tiny hole in the still hot solder. When withdrawn you have a pinhole size aperture. That way you do not defeat the fuel pump. Install so that you have a return back to the fuel line when you shut the car off and the pump is still on a pressure stroke. This way you do not have flooding and hard starts on hot days and so much carb "run over" Try it it works!

[55 Fargo]

Lots of good ideas and hints !

One of the old time tricks that will aleviate many headaches is the installation of a"bypass" on your fuel pump. Please excuse me if someone else posted this idea!!!

You need two tees , one for the outlet side and one for the inlet side of your fuel pump . they should be fuel line size x 1/8 compression. Next take a piece of 1/8 copper line long enough to go between them and solder one end almost shut-I use a piece of aluminum wire about the size of a straight pin to make a tiny hole in the still hot solder. When withdrawn you have a pinhole size aperture. That way you do not defeat the fuel pump. Install so that you have a return back to the fuel line when you shut the car off and the pump is still on a pressure stroke. This way you do not have flooding and hard starts on hot days and so much carb "run over" Try it it works!

I likes the idea, could you please detail your instructions on exactly how you did yours.......Thanx Fred

[Don Coatney]

Another option is to drill, tap, and install a fitting at the exact high fuel level in the carburetor float chamber. Connect a line to this new fitting and run it to the top of your gas tank. This is now the fuel return line. Then open the top of your carburetor, remove the float assembly and valve and throw them away. Replace the carburetor top and you are good to go. This is an old drag race car trick. No more flooding problems and no more leaks.

[moparalltheway]

Don,What size line works best? Could you do this and just leave the float in place? Like a overflow. Tank would have to be vented? Or use the vent line?