Edelbrock flooding w/o noticeable cause

[luvbowties]

Working on a customer's car with a 1963 327/250hp/stock. He has used a metal adapter to run a rebuilt, via NAPA, Edelbrock on the factory intake. The 250hp had smaller-bore intake with 4GC (?) carb. The 300 hp used a larger-bore intake with AFB(virtually identical to today's Edelbrock). His adapter fits well on both intake and on carb base. When not flooding, the carb-and-engine perform like new, from very slow driving even in 4th gear(4-speed Muncie) thru 120++(many of the +'s: speedo only registers 120).

At times, the carb floods(runs over top of carb and down the sides onto intake) with no apparent cause. I've driven it until it flooded, and quickly removed the tabs that hold the needles down into the jets, suspecting 1 or more needles having being raised too much and failing to re-enter jet; both were in correct position. Removed top for inspection: all correct. [NEEDLE AND SEAT HAVE BEEN CHANGED SEVERAL TIMES.] By time I re-assembled and started back up, it will run again, perfectly with no more issues for next 40-50 miles. Tried adjusting float level, new floats, rebuild kit, and no go. Fuel pressure via mech pump is normal for the carb, a bit low for original carb spec'ns. I seem to recall the Edel's and AFB's run better with around the 4-5 psi this pump produces???

My theory is the carb is simply getting too hot and boiling the fuel in the bowl, causing it to expand and flood. Anybody had a similar problem? I've tho't of changing the adapter to a phenolic or some material other than aluminum; or maybe even using a heat spreader/separator/dissipator plate. The flooding seems to follow no pattern, such as just after a wot-session, a sudden stop, slow-driving or fast-driving sessions. BTW: the orig. carb NEVER malfunctions. And the Edel NEVER floods when cold, such as soon after 1st daily startup--always after engine has been up to operating temp for a time.

Will appreciate any known solutions or even ideas and theories.

Anyone else think the heating could be the source?

Thanks to all.
Sam

[Rich 5150 69]

Sam I know you done the float issue, but still think thats the cause, either hanging up and not closing or just to much pressure, is he running a fuel pressure regulator...? I don`t think its a heat issue if the floats are operating correctly.

[cortcomp]

I'd wonder about that fuel regulator also, and be sure not to use the rubber tipped float needles, they're known to have issues with modern gas.

[19666Trucker]

5.5 psi is the most you be running those carbs. I got the edlebrock fuel pump and it set at 5.5.
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[tincan1966]

My experience follows suit with the other comments- you almost have to run a regulator with these carbs.
I had the same issue when I was running an Edelbrock on my big block. the PO just stuck it on and it flooded constantly- never really ran over the top, but hot restarts were tough. Added a regulator and problem went away, and performance improved a bunch.

[Hx16457]

Regulator recommendations?
I have a manual fuel pump with Edel. 1406, running rich.
I have vac. checked, re-timed, adjusted air/fuel mix screws... yet still rich..
Fuel pressure is high 8-10, kind-of a cheap guage so it bouces....

Looking for nothing super expensive just something I can get from the auto parts store.... maybe?

[geezer#99]

What does he have for a fuel line?
I had an eddy I put the hard line on that ran from the banjo down under the linkage close to the intake, out the front and created the same problem you have. Swapped back to a custom bent line out to the side and along the valve cover and the problem went away.

[jayoldschool]

My Edelbrock will flood if I let the car sit for an extended period of time. The gas in the carb evaporates, float sticks down. To fix, I smack the carb with a screwdriver handle when I start it after storage. Works fine after that. Stock (replacement) pump on a 350, bent hardline from pump to carb, with a big Fram inline filter up by the carb.

[63suburban]

Went through similar issues after installing a edelbrock 1406 on a performer eps manifold. 72 4 bolt main 350.

Like already stated, fuel pressure needs to be kept in check.

In my experience I found there needs to be a spacer under the carb to insulate from heat.

Here is simple steps of what I went through:
I picked up a mr gasket fuel regulator and gauge. Made sure fuel psi did not go above 5.
Checked all floats seats- fine.
Was still having the problem of fuel boiling over when engine was stopped when hot.
Add a heat-insulating phenolic spacer.
Carb is no longer boiling over.
Hope that helps.

p.s. When I purchased the mr gasket fuel regulator. I noticed a lot of bad reviews about it leaking. Mine has been fine for a few months. But might want to look into alternatives if you got the $$. I was looking for a cheap regulator and sometimes cheap does not equal the most reliable. Don't want anyone to be stuck because they choose the cheapest option. If you go the mr gasket route, Do make sure to check the screws that hold it together are tight.

[doobiebro]

Might need to adjust the floats. Edelbrock sets them high new out of the box. I had to adjust my floats the 1st day I installed my new carb because of flooding. Also make sure fuel pressure is not exceeding 6.5 psi and should be like mentioned at 5.5 psi. Thats what my personal findings where...

[Irishbleueyes]

I run a 1" phenolic spacer with my Edelbrock and it never even gets warm. Try that and a fuel pressure reg and see what happens then..

[rideblue00]

I had a problem when running mine on the dyno. It flooded as well. The guy doing it took my carb apart and polished the float needle a little. No problems after that. He said it was hanging up on the sides of the bore.

[luvbowties]

Just wish to thank all you guys offering suggestions/fixes & let u know that we have been experiencing monsoon-like rains here in the upstate. Hence, customer has not offered an opportunity to try our next attempt.
I will let everyone know what our next try does.

I can say that the rains have bro't some days with cooler weather for at least parts of the day; this occurring with virtually no flooding instances is making me tend towards the "boiling" theory that several have believed may be the culprit.

Last communication, he hasn't experienced but 2 of the flooding situations in several weeks; both times, after letting it sit for a while(cooling off period???), it restarted and quit flooding on its own. This is what we recommended he do until we can get it into the shop for several continuous days--we want to have it for an extended period of time for testing purposes.

Thanks again to all for your helpful ideas. More thoughts will certainly be added to our list of trial fixes if some come in.
Sam