Old ethanol gas and how it affects carburetors?
#2679612
07/21/19 12:19 AM
07/21/19 12:19 AM
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Joined: Feb 2010
Posts: 18,493 Granite Bay CA
Kern Dog
OP
Striving for excellence
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OP
Striving for excellence
Joined: Feb 2010
Posts: 18,493
Granite Bay CA
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Hey there, I have a 72 Duster that sits for long periods of time. It is my Brother in law's car and he lives out of state. 360 with a Holley 600 4 barrel. Here in CA, the blend is supposed to be "up to 10%" but testing has been reported to be around 6%. Regardless, the color of the fuel in the filter and the bowls is a pale yellow green. The last time I put more than 3 gallons of gas in it was several months ago, maybe last fall? Not sure.I did put about a gallon in it recently since I didn't know how much was in it. My point.... The car idles fine. I did have to replace the needle & seat in both the primary and secondary bowls. Under a load, it sometimes backfires through the carburetor, It is not consistent like it would be with a bad exhaust valve or worn exhaust lobe, just occasionally. The ignition system is old. The engine bay wiring is old. The alternator is not charging even though I have tried three alternators and a different voltage regulator. Yeah....The car needs work as many do,,,,But my question is: Can old ethanol laced fuel cause a backfire like this OR should I be looking at the ignition system?
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Re: Old ethanol gas and how it affects carburetors?
[Re: Kern Dog]
#2679622
07/21/19 01:24 AM
07/21/19 01:24 AM
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Joined: Aug 2003
Posts: 43,157 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,157
Bend,OR USA
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Old bad gas with any ethanol can and will clog passages in a lot of carbs from corroding them Even Holley carbs . Unless they have the special coated bowls and metering plates for ethanol type fuel Me thinks the best way to get around this is to run the tank dry when you know it will sit for more than 5 or 6 weeks and then add new fuel to run it on when you start it up the next time. Can you get any non Ethanol pump fuel there If so ,even if it is 87 octane regular, use a tiny bit of it (1/2 gallon) to run it on before letting it sit so it cleans out all the ethanol fuel in the system
Last edited by Cab_Burge; 07/21/19 01:25 AM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Old ethanol gas and how it affects carburetors?
[Re: Spaceman Spiff]
#2679716
07/21/19 11:57 AM
07/21/19 11:57 AM
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Joined: Feb 2010
Posts: 1,645 Phila. Pa.
Mattax
top fuel
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top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
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He should stick to stuff he knows for video. Here's an example of umbrella check valve that got distorted. (first photo below) Ethanol is just one of many components in automotive fuel that are not refined petroleum. Any one of those components can damage rubber and plastics. Find an 'old timer' who remembers the fuel reformulations in early 70s (see the end of of post 9 here for example ). There was another big change with introduction of reformulated gasoline (RFG). RFG first used MTBE, now pretty much phased out. Generally contains eth these days. Ethanol street mixes do not evaporate quicker or cleaner. Rather more of the light end evaporates at lower temperature, and complete evaporation (100% of liquid evoporated) occurs at higher temperatures. Observe yourself. Take a couple ounces of your California summer RFG and a couple ounces of VP C9 or Sunoco GT or GTX and let them evaporate in something. That's not 100% fair test because race fuel is not the same as 1970 High Test. But the point is to see for yourself that today's pump gas doesn't do what Tony claims.
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Re: Old ethanol gas and how it affects carburetors?
[Re: Kern Dog]
#2683910
08/03/19 01:55 AM
08/03/19 01:55 AM
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Joined: Jan 2003
Posts: 5,315 Land 'O Lakes
RoadRunnerLuva
master
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master
Joined: Jan 2003
Posts: 5,315
Land 'O Lakes
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I do the same thing for my Duster. I use 91 octane NON Ethanol "REC". gas in it at all times...from the local CO-OP Elevator, about 20 minutes from me as well. And in the fall before it goes into storage..I add Stabil to the tank for good measure.
Plymouth Makes It!
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