Well, Carl that is an idea but the 2 carb set up has worked well for 9 years and their has to be a reason for the change in gas mileage. Then the cost of all the parts, the ones I took off I gave away.
Nine years is a long time to expect 2 carburetors to stay in sync. It is my understanding that when using 2 carbs, it is imperative that they be identical. It sounds like you had that state of identicalness in the beginning and it remained that way for several years. However, there should be no expectation that 2 carburetors would wear in an identical and equal manner long term.
The unequal wear can be in the throttle shafts or it could be from one of the carbs having the dreaded casting warp, which causes internal issues which are difficult to see.
There is merit in the opinion that 2 carbs is one too many for these engines.
Its hard enough to troubleshoot a carb issue when one is only running a single carb. Running a dual carb setup multiplies that difficulty X 2.
Carl
Still humble
