Looking for advice

[KB9GIB]

1969 GTX,

I have had this issue for years when my car sets for any time it acts like it looses its prime I check the vents even added a vented gas cap still does the same thing. I’m thinking of capping the return line to see what it would do with out it? Any thoughts on this would be appreciate. KB9GIB

 

[RemCharger]

You need some NOS 60's gas...
The new stuff just evaporates .
Maybe internal carb leakage

 

[Gus chiggins]

Today's gas evaporates at a higher rate than the older formulated gas. Ethanol, of course, is in gasoline today.

 

[ruffcut]

WOW! Nice ride. Have you given any thought to a small electric pump near the tank? That would solve your problem. ruffcut

 

[ruffcut]

WOW! Nice ride. Have you given any thought to a small electric pump near the tank? That would solve your problem. ruffcut

 

[dadsbee]

I'm thinking your fuel pump check valve is not sealing.. how old is the pump???

 

[JimCoronette]

1969 GTX,View attachment 1180174 I have had this issue for years when my car sets for any time it acts like it looses its prime I check the vents even added a vented gas cap still does the same thing I’m thinking of capping the return line to see what that would do? Any thoughts on this would be appreciate. KB9GIB

If you have an AVS, they dry up after a few days.

 

[Fran Blacker]

As soon as you shutdown the hot engine boils out some gas. The corn juiced fuel evaporates fast. As dadsbee said about fuel pump. An electric fuel pump to refill carb is another answer. If you don't want to use it full time get one your mechanical pump can draw gas through.

 

[QOTHL]

Any thoughts on this would be appreciate. KB9GIB

I have a 69 with an original Carter that I put AN fuel lines on that I might have to pump once and it kicks right over even if it's been sitting for weeks. The stock fuel system on another 69 usually takes one pump after turning the key and cranking it for about 10 sec then kicks right over even after sitting for a few weeks. The six pack has a Power Master starter motor and hits as soon as the key is turned, after sitting for weeks, no pump.

 

[KB9GIB]

I wished this one would keep its prime. I only run ethanol free gas I have replaced the fuel pump several times over the years. I’ll check some of the stuff everyone has suggested. I appreciate your input. KB9GIB

 

[Jerry Hall]

Most all of mine do that after sitting for a few weeks. I keep a squirt bottle with gas and prime the carburetor on cars that have been sitting for more than a few days. It saves wear and tear on the starter.

 

[dadsbee]

My Superbird and it's 440 can sit for months. Crank, then two taps of the pedal and crank again and VRRROOMMM. I haven't as much as turned an idle screw on the stock carb since I bought it in 1990!

 

[WileE]

Your best bet ? I guarantee would solve that issue INSTANTLY. Sell that car to me real cheap.

 

[68BabyBlue]

My Superbird and it's 440 can sit for months. Crank, then two taps of the pedal and crank again and VRRROOMMM. I haven't as much as turned an idle screw on the stock carb since I bought it in 1990!

Good point about the check valve. Had the same problem as the OP with my 440 Track Pak GTX with original Carter AVS when I first got it, new stock Carter fuel pump installed, and from then on, started just like your Superbird. Ran it on pump gas for four years until I sold it last spring. I can't help but wonder if the quality on today's replacement pumps has declined to the same degree as some other replacement parts, when I see the OP has gone through multiple pumps.

 

[Ron Keefer]

Yup, got the same problem as the OP with my Cross-Ram with Carter Comp Series carbs. After a week or more, the fuel has evaporated, and I have to prime. I pour a couple tablespoons of gas into each of the fuel bowls thru the passage next to the metering rod caps, and it starts great.
I figured the evaporating fuel would have to leave something behind, so I purchased a Carter AFB at a swap meet to see what it looked like inside. The amount of crude was amazing, I can't believe the car ran at all. So, the fuel evaporating is not just a problem on start-up, but the residue build-up in the carb can't be good. I may open one of the Comps this winter!

 

[joemish]

I'll trade cars with you. have 2 here.

 

[Agdog]

Add a spacer between the carb and manifold, wood and phenolic work the best IMO.

 

[Sweet5ltr]

As others have mentioned, add a carburetor heat shield & 1" open spacer if it's a dual plane intake manifold. Include a momentary switch for an electric fuel pump to prime the fuel bowls as well.