Technical Edlebrock carbs, hot start flooding.

I have two (new) 1404 E carbs on an old, old, old Offy 360 intake on the 283 in my roadster. Very low profile intake, no spacers under the carb, progressive linkage, rear carb is the primary. It runs great, despite being rather over-carb'd, the only issue I'm seeing is that on hot days, it floods when shut down and restarted after a few minutes. It always starts, but obviously way too fat. If the ambient temps are below 80, or the car sets long enough for the engine to cool down, no problems.
I'm wondering if the carbs float levels (they're right out of the box) are too high, and with the low rise intake they're soaking up heat and perking fuel out of the bowls, dripping down into the intake and flooding? It's no big deal to adjust these, or so it appears, but before I pull the tops off the carbs, does this seem likely? I also am thinking that some plastic spacers between the intake and carbs, to insulate them from the intake a bit might help. Engine runs at 180-190 always, the car has full, stock louvered hood sides, mechanical fan.
Otherwise, I'm super happy with this, the only issue I've had is that I had to open and adjust the idle screws on the secondary carb in order to get it to idle, number 1 and 2 header tubes stayed much cooler, so it must be very lean with the primary carb at the rear?

 

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Carbs need insulator gasket or insulator spacer.

 

Do you have a regulator in the fuel system. Edelbrocks don't like a lot of fuel pressure, they can't handle more than 4 psi and will run with less. I had the same set up on a 350 sbc and found they only needed to be leaned out a bit by adjusting the needles inside the carbs.

 

One vote for insulates spacers.

 

No regulator. Stock mechanical pump. This only occurs when it's warmer than about 80. Otherwise, lights right up.

 

Check your pressure. I vote for spacers too.

 

Obviously I have plenty of under-hood clearance for spacers...

 

Try insulators. Gas ain't what it used to be. It boils real easily these days.

 

There is roughly a 1% change in volume for every 19 degrees. I vote for spacers and maybe tweak the float down


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I put a composite spacer under mine(351W), and it seems to have helped that hot start issue. I, also have a regulator ahead of carb, with the stock mechanical pump.

 

The float levels do need to be checked, though, so you ought to plan on doing that while you have the carbs off to install the insulators.

I doubt it has too much pressure.

 

Years and years ago your fuel pump was repairable or rebuildable . In today’s world must are crimped throw away junk . The old good pumps had an orifice drilled between inlet and outlet to allow for fuel boiling or expansion to return to the tank instead of flooding your engine when you shut down hot . You can change to early pump , take it apart and drill the orifice if it doesn’t have it already and be good to go . Insulators will help , regulator will help also , but not cure the issue unless you get 100 % gas no Al K Hall in the mix .

 

Thanks Squirrel, doing both could save doing the whole thing twice. I wondered about that when I put those on, with the carbs nestled down low, almost in the lifter valley. It's a pretty intake, but it's not the best one, I'm sure.

 

I'm going to follow this thread for information gathering too.
Mine too has a spacer to reduce heat transference.
I had thought that heat-soak was the cause of fuel bubbling and my hot start flooding when I parked it for 5 or 20 mins, then restarted it with great difficulty.
I got into the habit of flipping off the fuel pump switch about 10 or 15 seconds before turning in the driveway or pulling in a parking spot. It made it easy to start as long as I remember to turn it off at the right time, or let the carb go almost dry.
That seemed to solve the hot start problem, but it's a nuisance that isn't a cure, but only a coping mechanism.
I thought about lowering the float level a tiny bit, but suspect that may make tuning even tougher. Maybe I should try it and see...
Maybe I should test the fuel pressure, but havent yet. I think it was a 3-5 lb pump when I bought it, but haven't actually measured it yet.

In the meantime, I'm still turning off my pump 5 or 10 seconds before killing the engine to make it easy to start again.

WHY BE ORDINARY ?

 

QUOTE "I also am thinking that some plastic spacers between the intake and carbs, to insulate them from the intake a bit might help. Engine runs at 180-190 always",
I think I would use something besides plastic. Phenolic if you can find it. maybe??

 

Might also help to insulate any fuel pipe between the mechanical fuel pump and the carbs.

 

These guys are all correct. Those carbs need low(4), fuel pressure controlled by a quality regulator, not the cheap round junk with the dial. Insulators a must, I use Edelbrock #9266 and they do the trick.

 

Plastic or phenolic (I'd use "four hole" spacers, not "open" ones) will do the job just fine. I've used both without problem.
I'd would as has been mentioned to check the floats. Do not...lower them too much, it will affect the way the fuel enters the booster ventury and possibly cause flat spot in the pickup when you hit the throttle hard.

And yes, I've seen "stock" type pumps put out 8+ psi. And again, as has been mentioned, that's too much for ANY street driven combination to handle.
But leave adding a regulator till the last effort.

Mike

 

Yeah, that's what I meant but I can't spell "phenolic".

 

I agree 100% with running a fuel pressure regulator and insulator. My mechanical pump was putting out too much pressure. After numerous times taking the carb off, opening it up, adjusting floats and cleaning it, I read somewhere (probably here) about adding a reg.. fixed it. Mine would load up at stop lights and such... not to mention the hot starts.

 

I second the motion of shit canning the dual quads and running three deuces. Oh wait, no one suggested that yet. Never mind.

 

Put a few drops of gasoline on your intake manifold next to the head just after you've shut it down. You'll see what the problem is very clearly. Take the air cleaners off the carbs and look down the carburetors with a strong light immediately after shutting the motor down. You'll see where the fuel is leaving the carburetors and entering the intake. You've got to be quick because the fuel vaporizes so quickly once it gets into the hot intake you may not see it. In fact, the fuel may be leaving the carburetor through the overflows and into the intake in gaseous form, not liquid. And, today's gasoline is so well refined that it also has very little odor if it's fresh so you can't rely on your sense of smell as we used to. Phenolic spacers will probably help somewhat, but lowering you engine operating temperature and reducing the underhood air temps will help also. But...you may not be able to solve the problem completely in hot weather because it's a fuel blend problem, not a carburetor problem. Good luck. Been there myself.

 

Yep
Heat soak
Follow Jim's recommendation

 

I had the same problem on my mom's 58. Put the phenalic spacer in and haven't had an issue with it since.

 

I like to use the fuel filter with the return line. Wix 33041. Having fuel return to the tank keeps the fuel in the engine compartment cooler and also prevents the fuel from building pressure. It does require a return line to the tank though so it might be a last resort.

 

I put a return line on a couple of them, it really helps. Great suggestion, if the insulators don't fix it. I used the 3 line pumps instead of the 3 line filter, because they were chevys and you can get whatever pump you want for them.

 

Fuel pressure too high.

 

Heat soak,
Heat raises the volume of fuel in the bowl and it boils or dribbles out. Just like a boil over on the pot sitting on the stove. Heat raises the pressure in the line and it feeds the hot fuel bowl more hot fuel to dump and boil filling the intake- maybe enough pressure to blow past the needle valve - double whammy.

For sure at least check your fuel pressure- everyone should know what pressure is being delivered out of the pump, it can be crazy out of a stock pump.
Dropping the float below the advised setting to compensate for engine off boiling fuel is not a very good idea. If they are set high upon inspection the drop them to spec. Dropping operating temps to compensate for engine off heat soak is an equally bad idea.

Keeping the carbs isolated from excessive heat is a much better approach. Reflective skirt and a spacer and blocking exhaust gasses from manifold and isolated fuel line and 3 port filter are all great for doing that.

Getting in the habit of holding the throttle open on hot starts may even be enough. You aren't by chance running an electric choke are you? Those things work off of time or seconds of the clock they are powered, not engine temps.

 

Final vote for heat soak!
It ain't so much the "carb's fault' as it is the shitty excuse for decent gasoline! Who ever dreamed up the "BRIGHT IDEA" to subsidize corn farmers to make gas-a-haul needs to be kick in the "corn hole"!
Corn is best used for eat'in and feed'in hogs....not making a weak excuse for fuel!!
Ahhhh...I feel better!
6sally6