Modern gasoline formulations and carburetors.

[lloyd3]

I am noticing something that I had attributed to other issues on my older carburated cars.  Gasoline seems to not stay very long in the bowls for a later restart, such as overnight. I had always dismissed the problem on my original 4428s AVS Carter on my '68 R/T as being a worn pivot. My sons little BBS Carter is doing essentially the same thing however.  I have been told by other old car guys that they too, must prime their cars after any extended storage  to start them.  Are others here experiencing similar issues?

[white]

Yes, same thing. I'm sure it's the ethenol.

[lloyd3]

I could be the ethanol, but I've also heard from people (in the gasoline formulating business actually) that newer fuels (in the last 10-years or so...) have substituted toluene (instead of phosphorus) as the anti-knock compound in their gasolines. I'm sure air pollution requirements (both Federal and State) have directly influenced this decision. This works fine in fuel-injected systems, but tends to volatilize-off in older (unpressurized) car fuel systems, thus producing the symptoms I and others seem to be experiencing.  The good news here is that the problem of fuel-system varnish build-up has essentially been eliminated.  The bad news is that the fuel you buy has very limited shelf-life if it isn't properly contained.  Carburated cars, by their very nature, can not properly contain such formulations.  Has anybody else here heard anything like this?

[Mike DC]

 
Yes, modern gas evaporates faster than older gas did. 

One option is to install an extra little in-line electric fuel pump.  (Like, so it only runs when you are holding down a button or something.)  Use that to manually refill the dry float bowls before firing it up.   

[70 sublime]

Is it really that bad when you come to think about it to crank the motor some before it fires to help get the oil moving ??

[white]

I always crank the motor over till I see oil pressure then I engage the choke.

[Kern Dog]

I have found that new gas not only evaporates faster but that it loses it's punch faster. The volatile compounds go bad first. 3 month old gas will go from clear to yellowish. 9 month gas may have an orange tint to it. At that point, any car with decent compression will run noticeably different than it does with fresh gas.

[69hemibeep]

My car with the carter does this but the one with the holley does not. Different bowl vents 

[lloyd3]

Interesting,  wonder how the Holley's do it?

[DAY CLONA]

Interesting,  wonder how the Holley's do it?

The fuel evaporates in my Holley sixpack and 4 bbl cars after just a few weeks if I don't start them, rather than crank them over to fill the bowls, I have a small squirt/squeeze bottle and I just fill the main carb bowl through the bowl vent tube, reinstall the hose/air cleaner and just light it off as normal

Mike

[Swampwing2]

My car with the carter does this but the one with the holley does not. Different bowl vents 

I switched from an AVS to a Holley style a while ago and the starting difference was huge. The AVS would be dry and would take about 30 seconds of cranking to fill the bowls and the Holly starts right away with just a couple pumps of the pedal before cranking. No other changes to the car at the time. I figured it was also the fact the Holley bowls are hanging over the intake (more isolated) and not sitting directly on top of it.

[Kern Dog]

It could also be because the Holley holds more fuel.

[b5blue]

I'm also noticing cold air bog. My Sidewinder heads w CH4B intake take a bit of time to warm up with no heat crossover. 60 degrees yesterday and just off idle the 440 wanted to fall flat on it's face even after a few minutes of running. 

[Paul G]

If I let my car sit for just 2 weeks I have to crank it over for a while to get some fuel in the bowls. Then it starts and runs fine. No big deal, just have to crank it some, and it starts. 

[daveco]

Uncle Tony's thoughts:
https://www.youtube.com/watch?v=2peeE3hv5Jk

[ramairthree]

Yep.  There's the alcohol and I can only find 87 octane ethanol free anywhere close to me.

None of my four cars with carbs will fire right up unless it's only been one to thee days or so since I ran it last.

[Paul G]

Uncle Tony's thoughts:
https://www.youtube.com/watch?v=2peeE3hv5Jk

Uncle Tony is right. Ethenol gas does have an upside. Evoprating away quickly reduced or eliminated varnishing of the fuel and clogging up of the carb. My cars have to crank when they have sat for a while. Doesn't bother me really.

[mrob]

Not trying to hijack the post - but what about vapor lock and E10? I find that E10 percolates more than ethanol-free gas which causes vapor lock with E10 in the summer.