Technical Anti drain back valves for fuel line?

Every time i start my Chevy from cold I have to turn it over for ages before it will fire. Runs fine once it has started and will start easy if used every couple of days.

I’m thinking it must be fuel draining back down the lines. Does anyone have any examples of what I can use to prevent this?

It’s a 235ci straight six with dual carters on an offy intake. Fuel line is hard and runs from the stock tank to a stock mechanical fuel pump, to a filter bowl, then to an ally fuel block. Then i have two short rubber hoses going directly to the carbs from the fuel block.



Any suggestions or alternative ideas welcome.

Thanks
LT

 

Had a similar problem with the flathead in my p/u. Installed an electric fuel pump back by the tank wired to a toggle switch on the dash. When starting after sitting for a while, just hit the switch for a moment or two and fire it up.

 

Not likely that it's draining back. Very likely that it's evaporating out of the carb vent.

The mechanical pump has two check valves in it, keeping fuel from flowing back to the tank. Part of the design.

 

The fuel in the line may drain back if the check valves are leaking, but that shouldn't affect the fuel already in the carbs.

 

Hearing many anecdotal tales of hard starts after sitting for several days. Gasoline formulations today are different, the volatility in particular.

The fuel doesn't need to completely evaporate out of the carb bowl, just the light ends. That's my theory anyway.

 

Be careful what in-line electric fuel pump you use. I have excellent luck with the "rattle" pumps (i.e. Facet brand, etc), they act as a one-way check valve with the power off.

Note, they come with different output pressures, must be matched with your carb requirements.

The new Edelbrock Micro in-line pumps are some sort of gear pump, they are very restrictive to fuel flow with the power off. In my Off-Topic Commins diesel conversion, I used an Edelbrock #17302 as a priming pump. Hit the prime (momentary contact) switch, fuel pressure quickly reached 8 PSI, released the prime switch, started the diesel, and watched the fuel pressure drop to Zero. Back to the drawing board.... <sigh>.

 

Perhaps it is your accelerator pump not working.

Sent from my SM-T350 using The H.A.M.B. mobile app

 

I have to start mine every day to avoid excessive cranking with twin Rochester AA back draft carbs. These have a very tiny fuel bowl which evaporates fast, and we can't buy the better gas here.

I need to replace the Facet priming pump that failed last year. That does work for cars that sit for days.

I'm thinking I might hook up the chokes to try that first.
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Any deathanol ever gets in the pump, it's going to leave that white crap everywhere, causing what you have. Even before corn gas was thrust upon us, I always had an electric pump on 6 volt cars just for long periods of idleness.