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brown7373 · 07-07-2018, 12:16 PM

That rectangular opening in the back is for a hot idle compensator that some models have. If so equipped, the larger round hole 2/3 down in the rectangle would be open and a spring valve would cover the hole and open when necessary. Then a cover attached at the two holes would cover the opening in the casting. I'm not sure if the Idle Comp was used if it also had the hole in the top you referenced.

07-07-2018, 12:16 PM	#3
brown7373 Registered User Join Date: May 2011 Location: Fort Pierce, FL Posts: 430	Re: Quick carb rebuild question That rectangular opening in the back is for a hot idle compensator that some models have. If so equipped, the larger round hole 2/3 down in the rectangle would be open and a spring valve would cover the hole and open when necessary. Then a cover attached at the two holes would cover the opening in the casting. I'm not sure if the Idle Comp was used if it also had the hole in the top you referenced.