Fuel System: Carburetor Carter WE-715S

[perichm50]

1950 Champion- rebuilt orig 6--Having issues with carb loading after medium distance drives (25-35 miles) when everything is nice n warm. Have rebuilt carb with kit and adjusted float a couple times. Timing has been checked and slightly advanced. I am out of ideas on adjustment. Seems to run fine around town


Any ideas? I have even considered going with a 2 barrel carb set up but not sure what that will do for this engine. More interested in reliability/performance than originality.

[StudeRich]

Have you very slightly LOWERED the Float Level for today's oxygenated and Methanol laced Fuel?

Check the Fuel pump Pressure, it may be too High requiring a Pressure Regulator.

[karterfred88]

I think Rich is onto something regarding fuel pressure. I'd buy a cheapo $20.00 regulator, insert in the gas line to the carb, set it to 4 1/2 lbs. and see if the problem disappears.

[perichm50]

I did not lower the float. Will try that and figure out how to test the fuel pressure. Book says 4-5 psi...that seem right?

[doofus]

Might it be trying to vapor lock? Try insulating the fuel line from pump to carb .Luck Doofus

[perichm50]

Might it be trying to vapor lock? Try insulating the fuel line from pump to carb .Luck Doofus

I wondered about that. I wasn't sure if vapor lock only happened after shutting car off when hot or if it could begin while running....

[DEEPNHOCK]

I wondered about that. I wasn't sure if vapor lock only happened after shutting car off when hot or if it could begin while running....

Vapor lock can happen either way, and it can be pressure related as well as temp related.

Example: Gas (like water) boils at a certain temp at a certain pressure.
If you get the temp 'close' to the boil point, and then reduce the pressure (say, at a pinch point in the line..like a 90 degree fitting)..
Then the gas can boil at that point, introducing that bubble that won't burn.

All an electric fuel pump does is raise that pressure point in the supply line and eliminate that low pressure point that was the start of trouble.

A good, free flowing supply line, when used with a mechanical pump won't have that low pressure point.
That's why some mechanical systems don't have problems.

Insulating the lines to keep the temps down definitely helps, with either setup.

A bypass return line also helps, by keeping everything stirred up and at a more even temperature.

I would agree with the previous suggestions about changing the float level a little bit.
Keep a log book of your changes, so you can back up a step if you go too far.

HTIH (hope the info helps)

[karterfred88]

Besides the simple sheet metal "heat deflector" there doesn't seem to be any thermal break between the carbs and intake/exhaust manifolds on these engines. Does there exist a single barrel carb spacer/insulator for these engines? Like Chevy used. It might help, if boiling fuel is the problem. Cooling the carb itself off, would be more effective than trying to keep the fuel cool getting to it.

[altair]

There are a couple of different design manifolds and cast bases for the WE carbs. On one model the heat riser only heats the manifold and the other model the heat riser heats up in to the cast base. I have two WE carbs complete with the cast bases but the cast bases are different. The model with the heater going up into the cast base is the 715S. Perhaps your heat riser is over cooking the carb and fuel

[gordr]

Also check to be certain the float valve body is securely seated in its bore in the carb top. I encountered one in a '50 Champion at the Spokane International Meet (some folks here may remember that incident), where the float valve had backed out about 2 turns, to the point that the float in its lowest position was holding the float valve tightly closed. However, enough gas leaked around the remaining engaged threads of the valve body that it it would flood out at idle. But get it running, and try to drive, and the fuel in the bowl would soon be consumed, and the leakage around the threads was not enough to keep the engine running at part or full throttle, and it would lean stall. A head-scratcher! And the first time I had the top off the carb, it wasn't completely apparent that the float valve had unscrewed. It sits in a bit of a well, so the unengaged threads are mostly hidden. Unless you know to look for it, it doesn't leap right out at you.


If I remember right, there is a copper washer used to seal the float valve body to the carb top. New copper washers are annealed, and dead soft, and crush a little when the valve assembly is tightened in place, making a seal, and securing the valve against rattling loose. Used washers become work-hardened, and as a result don't afford the same sealing and locking properties. But you can anneal copper by heating it red hot and allowing it to cool slowly in air. That makes a huge difference in the hardness of the metal.

[altair]

Also check to be certain the float valve body is securely seated in its bore in the carb top. I encountered one in a '50 Champion at the Spokane International Meet (some folks here may remember that incident), where the float valve had backed out about 2 turns, to the point that the float in its lowest position was holding the float valve tightly closed. However, enough gas leaked around the remaining engaged threads of the valve body that it it would flood out at idle. But get it running, and try to drive, and the fuel in the bowl would soon be consumed, and the leakage around the threads was not enough to keep the engine running at part or full throttle, and it would lean stall. A head-scratcher! And the first time I had the top off the carb, it wasn't completely apparent that the float valve had unscrewed. It sits in a bit of a well, so the unengaged threads are mostly hidden. Unless you know to look for it, it doesn't leap right out at you.


If I remember right, there is a copper washer used to seal the float valve body to the carb top. New copper washers are annealed, and dead soft, and crush a little when the valve assembly is tightened in place, making a seal, and securing the valve against rattling loose. Used washers become work-hardened, and as a result don't afford the same sealing and locking properties. But you can anneal copper by heating it red hot and allowing it to cool slowly in air. That makes a huge difference in the hardness of the metal.

To anneal copper you quench it in water to harden. If a non ferrous metal is cooled over a long period of time it will become hard. However because of the limited volume of a small copper washer air cooling would not be much different than quenching in oil or water. Hundreds of years ago weapons were made of bronze heated and cooled over long periods of time, sometime packed in lime for weeks to cool. Copper and brass will work harden, if you need a tight bend heat the tube and quench it in water and it will become soft.

[Lothar]

Altair and Gord
Great information and details about the WE-715S (I didn't know what the "S" stood for until I read Altair's post about heat risers). All that said, my money is on a vapor lock as the source of the problem. I would bet that insulating the fuel line between the fuel pump and carb would resolve the problem. That is at least the easiest thing to check first, before you get into annealing copper, by whatever method that is done.

[gordr]

The whole purpose of annealing copper is to soften it, not harden it. I have never had to quench it in water. Quenching usually hardens metals.

[altair]

I messed up my first line in my post. To anneal copper, you heat it to cherry red and quench it in water. To anneal steel, heat to cherry red and let it cool in the air or insulate to cool over a longer period of time. To harden steel heat to cherry red and quench in cold water, hot water, bacon fat or mineral oil. Rarely copper is hardened but it can be hardened by mixing with other alloys such as tin, it can also be hardened by extending the cooling process as long as possible. This is a very technical process that should be left to a metallurgist. There is some good information on Google about the process of softening copper.

[perichm50]

So while working on this vapor lock issue, I discovered gas in the oil. Fuel pump has been replaced with a new unit, oil drained a couple of times, and carb cleaned and float reset. Now engine cuts out like it is gas starved under load. Re-cleaned carb, reset float back to standard 3/8 per repair manual and no change. Reset timing, still have this problem...that only showed up after fuel pump replacement. Having a circular argument with myself. Thoughts?

(I have not put an inline fuel pressure regulator in as suggested for vapor lock)