Re: 8N popping/sputtering at idle

In Reply to: Re: 8N popping/sputtering at idle posted by Ed Gooding (VA) on June 12, 2026 at 15:10:21:

In an earlier post I mentioned that I had followed Bruce Haynes’ carburetor adjustment algorithm and currently have the idle mixture adjustment needle turned out 1/8 turn. I can actually close (all the way in) the idle mixture adjustment needle without any noticeable change in the popping/sputtering/roughness/RPM.
I read with interest your post concerning the economizer jet. I read some additional information on the Marvel-Schebler economizer jet. As I understand it, the economizer jet works by resolving a rich fuel mixture by introducing additional air into the fuel mixture creating a leaner mixture. There was a reference to Service Bulletin 118 but I was unable to locate it.
As I see it, I have too much air in the system because I can actually close the idle mixture adjustment needle. I have searched for an air leak using a propane torch and also a can of carburetor cleaner without finding an observable air leak either time.
Please advise what additional measures I can explore.
As always, your comments are appreciated.

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