The effects of OLD gasoline in a classic car

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Kern Dog

Kern Dog

Build your car to handle.
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Although I enjoy the show, The Walking Dead really stretched the truth in many ways. They had people driving cars YEARS after the world crashed using gasoline that was several years old.
That would never work here in California.
Our gas is "Up to 10% Ethanol". Testing has found it to be approximately 6% as of 2 years ago. I've read that the Ethanol gas has a shorter shelf life than pure petroleum based gasoline.
I have had a persistent cold start problem with my Charger for several months. The last time I drove it to a gas pump was early this year. Since then, I've driven it less than 100 miles. I've been working on several things with it including a new Classic Auto Air heater and A/C system, wiring upgrades, windage tray, radiator, water pump and housing...all sorts of things. Because of that, the gas in the car got old.
So, since about June of this year, it ha been hard to start and when it did, it ran really rough. The Air/Fuel gauge read really lean as well. It slowly smoothed out as it got up to temperature. Once it was warm, it ran great. The Air/Fuel readings read rich as it warmed up, with numbers in the 12 to 12.5 range.
I looked for the causes of the rough cold idle. First off, I did NOT have a choke on the carburetor. This Demon 850 always allowed the 440/493 to run pretty good at cold starts without a choke. 20-30 seconds of feathering the throttle and it would run on it's own. The rough running felt like a serious misfire, as if 4 holes were just not getting spark. I swapped parts around including the distributor, spark box, ballast resistor, coil and I even tried a different carburetor. The Holley 750 from another car was the only thing that made a difference. With it, the engine ran like it used to before any of the problems started. I had my Demon rebuilt and the man installed a new electric choke kit. Yesterday I put the 850 back on and the car ran just as bad as it did before. What the heck?
It turns out that this 11 month old gasoline was the problem. Today I drained the tank and the bowls of the carburetor and poured in fresh 91 octane gas. The car runs great again.
Why did it run good with the Holley 750? I think that it was because it still had gas in it from the other car!
MY understanding, after reading up a bit, is that as gasoline ages, it evaporates and loses the volatile compounds first. This leaves behind a thicker, yellower and less potent blend. Cold starts need MORE fuel than a warm start. The fuel needs potency to ignite.
I guess I'll keep some Sta-Bil on hand if I think the car will sit for more than a month.
 
I always drain my sleepers and fill the lawnmower with that crap, or the 7:1 slant will burn it no problem..The new stuff is also hygroscopic so it absorbs moisture too. I filled a little water bottle out of a jug to fill a weedwacker and I left the top off, 4 hours later the gas was yellow. That's like 'Waterworld' where they are still running waverunners and we all know those motors dont last for more than about 5 years.
 
I start all my cars at least twice a month and add gumout to every tank and have never had a fuel related problem. Been doing it since I bought my dart in 1981
 
Gas that's not gummy but old goes in my 2004 Toyota truck. EFI system adjusts so car burns it with no issues. Been doing for awhile.But as said in post #2 I do runs my Lawnmowers 1st as the tank and carb. bowl are easy to remove if necessary.
 
Do you have the option of ethanol-free where you live? If you haven't seen this site before, it can be helpful: Ethanol-free gas stations in the U.S. and Canada

For me, anything I have with a carburetor gets the ethanol free. I also run E0 in my Duc which is EFI but has a nylon tank that absorbs the moisture that the ethanol absorbs out of the air, then starts expanding to the point it causes problems. The problem was so bad there was a class action law suit over it and Ducati gave everyone a one-time new free tank even though the bikes were way out of warranty.
 
Kern Dog said:
Although I enjoy the show, The Walking Dead really stretched the truth in many ways. They had people driving cars YEARS after the world crashed using gasoline that was several years old.
That would never work here in California.
Our gas is "Up to 10% Ethanol". Testing has found it to be approximately 6% as of 2 years ago. I've read that the Ethanol gas has a shorter shelf life than pure petroleum based gasoline.
I have had a persistent cold start problem with my Charger for several months. The last time I drove it to a gas pump was early this year. Since then, I've driven it less than 100 miles. I've been working on several things with it including a new Classic Auto Air heater and A/C system, wiring upgrades, windage tray, radiator, water pump and housing...all sorts of things. Because of that, the gas in the car got old.
So, since about June of this year, it ha been hard to start and when it did, it ran really rough. The Air/Fuel gauge read really lean as well. It slowly smoothed out as it got up to temperature. Once it was warm, it ran great. The Air/Fuel readings read rich as it warmed up, with numbers in the 12 to 12.5 range.
I looked for the causes of the rough cold idle. First off, I did NOT have a choke on the carburetor. This Demon 850 always allowed the 440/493 to run pretty good at cold starts without a choke. 20-30 seconds of feathering the throttle and it would run on it's own. The rough running felt like a serious misfire, as if 4 holes were just not getting spark. I swapped parts around including the distributor, spark box, ballast resistor, coil and I even tried a different carburetor. The Holley 750 from another car was the only thing that made a difference. With it, the engine ran like it used to before any of the problems started. I had my Demon rebuilt and the man installed a new electric choke kit. Yesterday I put the 850 back on and the car ran just as bad as it did before. What the heck?
It turns out that this 11 month old gasoline was the problem. Today I drained the tank and the bowls of the carburetor and poured in fresh 91 octane gas. The car runs great again.
Why did it run good with the Holley 750? I think that it was because it still had gas in it from the other car!
MY understanding, after reading up a bit, is that as gasoline ages, it evaporates and loses the volatile compounds first. This leaves behind a thicker, yellower and less potent blend. Cold starts need MORE fuel than a warm start. The fuel needs potency to ignite.
I guess I'll keep some Sta-Bil on hand if I think the car will sit for more than a month.
Click to expand...
Sounds like you need to drive your car more or don't put as much in the tank. You can use Sta-Bil or even Marvel Mystery Oil. I usually start mine a couple times during the winter but they don't run long enough to burn much gas. We are lucky here in Iowa. We are the largest ethanol producing state but many gas stations have non alcohol 92 octane.
 
Is the electric choke hooked up? If yes, these need adjusted to increase or decrease the speed as to which they come off choke.

For either the Holley or the Demon, was the high idle in use?

I have experienced this with my truck, a mild built 460 Ford with a 3310 Holley. It sits a lot, it will run somewhat poor until I fill the tank then its back to normal.

I'm still using gas in my lawn mower that was in my Dart 5 years ago, and it sits in my shed in a sealed container. The mower is hard to start, but its older, once it fires it don't quit until I do.
 
Six different states, and six different stories. Makes since to me.
For me I really liked post #6. Nice web site. Have to call the marinas to check if they will put it in a car or if ya need a gas can.
STA-BIL 360 "MARINE" IS THE BEST
The boaters have a bigger water problem than most of us. Most boats have to run a water separator filter.
 
Sea foam. Also a stabilizer. i use it in anything parked for any length of time.
guy had a corvette, put it in storage at my place, didnt do anything about the old gas,and blew engine the day he took it out of storage. It started detonating on the highway and that was the end of it.
There could be more to the failure,bad distributor, plugged jets in carb and so forth.
 
oldkimmer said:
I use sea foam also. I have witnessed it do incredible things. ...
Click to expand...
Hell yeah! :rofl:

maxresdefault.jpg
 
Keystone said:
Do you have the option of ethanol-free where you live? If you haven't seen this site before, it can be helpful: Ethanol-free gas stations in the U.S. and Canada

For me, anything I have with a carburetor gets the ethanol free. I also run E0 in my Duc which is EFI but has a nylon tank that absorbs the moisture that the ethanol absorbs out of the air, then starts expanding to the point it causes problems. The problem was so bad there was a class action law suit over it and Ducati gave everyone a one-time new free tank even though the bikes were way out of warranty.
Click to expand...

Wow,
That list you linked to is really helpful and I've got a station right here in town. THX
I've got a 65 that is driven enough that it hasn't been a problem. The six fours got 106 race gas and that stuff is like good forever. After draining and cleaning the tank and rebuilding the carb last wknd, I'm actually in the process of redoing all the lines on my 69' that had sat for a while and had planned on using sta-bil or Seafoam going forward but will now additionally use the 92 octane ethanol free available.
 
In 2015 I drove my F350 back home to WI from LA and started out with 37 gallons of 11 year old gas. At $4.00 per gallon there's no way I was draining the old stuff
 
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I’m late to this thread but, can concur, Seafoam is Magic in a bottle. I try to treat all my vehicles once a year with a full bottle. The stuff works wonders (even in newer vehicles).
 
Try dribbling a water hose in the carb at a fast idle. Watch the black stuff come spitting out the tail pipes. Careful you dont go crazy with the volume, just enough to drop the RPM' by a few hundred.
I had a power brake booster lose a seal and it almost sucked the MC dry, smoked like that Ferrari on Sea Foam, same thing happens when a Ford trans modulator goes south.... Lost a piston pin C-clip (or forgot to put it in) on a 2cyl Honda 600 and it wore a groove in the AL cylinder. Burned oil like a sky writing plane.
 
If you seal the container and keep it out of the sun, even the crappiest gas can age well.
Try it for yourself.
Take two glass quart sealers, fill them halfway with fresh 10% gasohol, and mark the level, Then seal one of them, put it in a cool dark place. The other one you leave open, and in, indirect sunlight.Take a picture of that one every 7 days until it turns dark orangy-red, noting the liquid level.
After two weeks, pour some of that crap gas on the concrete floor and see if you can light it, and if you can, watch what it does.
Now go get that other one, and do the same.
Shazzam!
I used to do this test for A-holes that brought there stuff back to me for warranty, saying I screwed up; and insisted their gas was fresh in their whatever equipment. I'd say something like "'Hang on jerkoff, lets see if your fresh flipping gas will burn". So I poured out some of his gas and with a bar-B-que lighter , got it going. And there was his gas sputtering and smoking and stalling out.
Then you see the A-hole do one of two things; own-up or efoff.
Either way, there was no more talk of warranty.
Sometimes I even made a new friend. No not the efoffer.
That was a long time ago; I don't talk like than no more.
 
Oh so the cool, dark place gasoline is always kept in ain't good enough? You know....the GAS TANK? LMAO. yeah, ok.
 
Gas tanks for cars with carbs are 1) ventilated, and 2) sit outside in whatever ambient, from 35 below to 110 above, breathing the same air you and I breath, with every change in temperature. If that air happens to have moisture in it as often it does, then that too will get into the gastank..... while 3)the VOCS are constantly abandoning it.
But yur right the gas tank is dark, so what; this is a color test.
I know you know this so why are you ragging on me again? Go have a beer.
 
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