SC cars flooding when hot

On the 851 (non-s/c and one of the more driven 851 cars in the club), I have all steel lines and I also have the line wrapped with an insulation (in tube form) made for racing - I have the insulation a little large as the line was already made and I needed something to slip over the ends. When I stop after a long drive I actually hear the fuel boiling in the bowl and I am thinking about a thicker carb to manifold gasket. The car runs on a low pressure 12 volt in the tank pump that on 6 volts operates within acceptable range.

I am still running my 41 Cadillac on the original fuel pump (no electric pump) with all steel lines and "clothespins" - and the clothespins are actually in a "fix" in the service bulletins for limousine service. The other problem they had was that heat built up under the rear axle in the cars with fender skirts, so they had to cut the line and install flexible gas line hose. With the changes in gasoline though, I probably will install an electric pump very soon.

I installed a steel fuel line between the fuel pump and the carb. Steel seems to keep the gas cooler than copper tubing.

I use a electric Carter Gerotor pump. It is a 12V pump I run on 6V for a fuel preasure at the carb. of 3 lbs. on the Cord. I run through the orig. pump for the flow back valves. The orig. pump has a plate in place of the dia. with another between the block and pump to keep fuel out of the crankcase in case of a problem. I also use a preasure swith on the oil line that will shut of the pump if there is low or no oil pres. I have never vaper locked in this car including 10 mile pulls up 9% grades.
CORDially Mike

another trick that I have used is to place wooden clothes pins (the clamp type) on the fuel line. these act as a heat sink, and can be easily removed for showtime.

I should have pointed out that I have a fuel pump regulator between the carb and the pump. I also put a pressure gauge between the carb and the fuel pump.

Another solution for hard cases:
Install a return line at the carb inlet, back to the fuel tank. Its important to install a reducer in this line, in order to have enough pressure at the needle valve, but leaving an open return for vaporized expanding hot fuel. You also will have alway more fresh and colder fuel in the fuel lines.
Good luck,

Andreas

TOM~
4,0 PSI might just be a just s bit to high ! ?

I have had this same exact electric pump cause problems with several carbs on cars that I own.
I have had this exact fuel pump overpower the float on several old carbs.
I find that they do not really accurately control fuel pressure.

You might wish to augment this fuel system with a Holley low pressure inlne fuel regulator just down-line of that Airtex fuel pump. That Holley fuel pressure regulator can be bought very cheaply at most speed performance shops & mail order supply houses.
Keep the top fuel pressure at about 2.0-2.5 PSI at the max !

Re-check your carb's float shut-off level and be sure that the float's needle & seat valve are totaly shutting off your carb's fuel supply when needed.

I'm using an electric low pressure fuel pump (2.5-4.0 PSI) made by Airtex Products. It is 6 volts piston type pump, their part #E8902. Most part stores don't stock it. You may have to order it from their web site.

Mike~

I really don't like the idea of lowering the float level more than the carb's original specs as a band-aid-fix.
When you lower the float level you may lean the engine's fuel/air mixture to much and cause performance issues as well as causing severe engine damage such as burning the piston tops & valves from running way too lean a fuel/air mixture.

With modern fuel / ethanol blends I find this exact same issue you seem to be having .
Modern fuel blends are really designed for high pressure fuel injection and not old carbs.
Here the Summer & Winter fuel blends we are forced to use by the government mandated EPA regulations only complicate this issue.

With this exact same issue you are now having I was afraid of a fuel fire from the gas dripping out of the carb's inlet flash screen while sitting at rest while still very hot after a long hard run .

First I checked my float level and it was spot on factoy spec.
Next I removed my float valve needle & it's matching seat.
This R~R needle assembly does not have any rubber tip but it is made from monel so i decided to re-lap the nedle & seat with very fine valve grinding compound mixed with #30 oil.
I was then sure I had a liquid tight needle & seat seal.
I re-installed the needle valve assembly and my problem of fuel dripping still persisted

I never had these issues with good "old fashoned" low test gasoline designed for old carb systems which you cannot find around anymore .
On my Springfield Rolls~Royce Phantom I finally found I had to re-locate the fuel line that runs near the exhaust manifold down to the updraft carb comming from my Stewart~Warner vacuum tank style fuel pump.
I hated to alter it's original stock location~~~
It does not look very great cosmetically~~and it sure is not the stock original copper line routing anymore.

But after slightly moving the copper fuel line I soon found my heat related carb fuel perking & flooding + dripping problems were totaly cured.

You idea of keeping that heat off the fuel line with insulation is a Great idea.
Some sort of simple removable carb & fuel bowl heat shield may be another good idea also ?
A carb heat shield that you can easily remove for car show events to maintain the engine's look & originality.

Are you using a modern electric fuel pump; or the original stock Auburn & L-29 Cord fuel delivery systems on your cars that you tour long distances in ?
OR~
Do you just use a hidden electric fuel pump as a back-up ?

I have found that it's very hard to find an electric fuel pump today with a very low working PSI pressure that will not push the float valve's needle off it's seat on these very old carbs.
Possibly adding an inline fuel pressure regulator such as the Holley inline fuel pressure regulator may help some folks who are using a modern electric fuel pump with similar problem issues as you are experiencing ?

I had a expereance that might help some one else. I have my floot level in the carb. set at 3/4". The specs. say 5/8" So my floot is set lower than specs because when I drive for a couple hours at 60 MPH and make a quick stop for bathroom etc. and try to start again the car is flooded and I have to crank for a while with my foot to the floor to get it started and I smell gas. On a trip to Ohio last week I decieded I was going to find out what was happening. I made a stop as normal but immidiatly took the floot cover off the carb. and looked in. What I saw was fuel coming into the bowl from the needle and seat and gas was close to the top of the bowl thus flooding the carb. I have determined that the gas in the line from the fuel pump to the carb. was expanding with the car shut off because of the added heat with no air flow through the engine compartment and since it can't go back through the fuel pump because of the check valves it is overcoming the needle and seat and entering the floot bowl. The solution I am trying is to wrap the fuel line in insulation tubing I bought from Summit Racing. I'm hopeing that will keep the heat off the fuel line and eliminate the flooding. I'll see through the summer as we have some other long trips yet.
CORDially Mike