Weber carburetor
 

Has there ever been a solution for the long cranking condition with these carbs on 454/7.4 engines ? Every discussion I find seems to die with no solution or suggestions to replace the carb, rebuild the carbs, check valves in tank or add electric fuel pumps.
Everything works fine until the boat sits for a few days and then the problem surfaces.
Ed

let it sit a couple of days. take fuel line out of carb. add a short piece of hose and put into a bottle. crank. does it start pumping fuel immediately? or does it take about as long as the no-start takes? an AFB will fill enough to fire with about 2 shots of the fuel pump.

2-3 days it starts immediately. Wait any longer and the problem arises.

Also I installed new mechanical fuel pumps last summer. No difference.

It's leaking or evaporating. Best thing to do is remove after run. And check underneath a few times a day to look fora wet spot.

Quadrajets are more famous for this and the above is what I do. Usually, but not always, the little welch plugs.

What and where is a Welch plug ?

The pressed in plugs on the bottom of the carb. It's thought that the fuel seeps past these plugs and evaporates out of the intake when the boat sits for a few days.

I've fought the same issue for years with the same carb, I usually just squirt a couple of seconds of starting fluid into the flame arrestor after it sits for awhile to get it going quicker rather than cranking the engine forever.

I always had better luck with mine by breaking myself of the habit of cranking the engine with the throttle partially or fully open. Return the throttle to the closed position after a pump or two and if the choke pull-off is set correctly it should pull in enough fuel for a reasonably quick start.

Still, I don't miss carbs one bit.

fuel will evaporate sitting, the webers do not have the the plugs that leak like the Q-jets, want to start quick add electric fuel pump, and make sure the choke is working, they do not like to start without a choke, edelbrocks with elec choke are great bolt on replacements for std non performance applications

The edelbrock carb is a weber (believe they bought them in the 90's? Still say weber on the casting). Agree with all of the above, the fuel is probably just evaporating out. Its hot, and the engine compartment is like an oven if the boat is in the sun covered.

My Formula 206 has an electric fuel pump, it can sit for weeks, I just turn on the fuel pump, let the bowl fill and it fires right up. Previously with the mechanical pump, I would have to crank it for about 10 seconds before it would fire if it had been sitting.

I've been doing the same with starting fluid. It only takes a quick squirt into the arrestor and the engine fires and fuel gets pulled into the carb. Trying to save long cranking on the starters.
Would like a fix though.

I messed with mine for 3 years and never got it to fire quickly after sitting a week. Always had to use starting fluid. Tried all the fixes above, none worked. No leaks - mine at least was evaporating.

Did a mild warm up of the engine and changed to a holley 850. Now, It can sit for well over a month and fire easily. Pump throttle once, turn key and it fires within a second or two.

IME, the webers just allow evaporation of the fuel.

The old carter on my Mopar does the same thing. Evaporates out of the bowl. I use a mustard bottle to fill the bowls before cranking.
I'd refrain from using starting fluid if possible.

Would a phenolic carb spacer help?

Makes a huge difference in heat to the carb since it is the super heated intake manifold (OE carb intakes have open exhaust crossovers in bottom of intake - not the Vortec sbc's though) that causes most of the heat.

2-3hrs after the engine is shut down....no difference.

Mine does it too. It cranks for about 5 to 8 seconds and starts cold. Electric pump. I may wire a prime button.

Same problem when I had the Weber on the SBC in my bowrider. When I did some work to the motor I swapped to a Holley and never had an issue again. My Regal with Weber's on 454's does the same thing.

Had the same issue with a Weber on a 454mag. I swapped to a Holley when I did some upgrades.