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I believe I got some bad gas, need some opinions/advice.

The car was running pretty nice with the Holley 670 Ultra on it.  Yes I thought the Fast Idle held on a little too long, but after about 10 minutes it kicks out and had a great idle.around 900 RPM.

Last Saturday I ran some errands and went to get some gas at BP like usual.  The card machine was not working on multiple pumps so I got fed up and left.  Went to Phillips 66 and filled with their premium, then went home.

Later that evening I took the car to a cruise night.  The Fast Idle did not engage and my 7 minute stop and go drive to the cruise night resulted in a lot of fanning the throttle at stops to keep it running.  When I drove it home, it was a real challenge and it would not idle at all.

I checked for any signs of a vacuum leak, the added Octane boost to the tank.  A couple days later I decided to try her again.  44 miles later, it still won't idle and had some hesitation at some transitions on the highway.

Is there a way to back the metering jets out and clean the idle circuit while the carb is on the car?  What else do you suggest?


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Use some carb cleaner and a small wire to make sure the idle air bleeds are not blocked. It does sound like bad gas from your description. Long story but I had a tank full of "bad gas" 2 years ago. I ended up changing the, the lines, the tank, and rebuilding the carb. Everything was covered with a grey substance. It took an ultrasonic cleaner to get the carb clean. Let us know what you find out. Chuck

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Thanks for the reply.  What do you mean by the idle air bleeds?  Is that where I take the idle mixture screws out and clean those ports?  Or are you talking about a full removal and bench top dismantle and cleaning.

I guess I need to burn through the other Half tank of gas on the highway so I get that crap out of the way.  Are there any recommended fuel system cleaners that will help with this?  Sea Foam, Gum Out, etc.  I figure those might help, but I do NOT want to erode the aluminum carburetor.

 Let me know.  I want to work on the driving stuff again, not this type of crap!


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Drain out and run in your other car.  Try to run Ethanol free fuel.  The alcohol is very bad on carbs. Berryman’s chemtool fuel system cleaner is my personal  favorite.  My old Kawasaki’s carbs get gunned up easily and often.  I put The whole can of Berrymans in and it will usually clear them up in 100 miles (in about an hour....)

Link to my 72 Q code: pics added 2/16/19



Link to my now sold 72 H.O



My 70 Boss racecar




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