|
I noticed you're filling up your tanks pretty quick, with only an average of 162 miles. That magnifies errors caused by topping off or automatic shut off at the pump. The longer you go in a tank, the more those fractional gallon differences will matter. Yes, I know it means less feedback, but if your feedback is filled with noise, it's hard to know what changes are meaningful and what aren't.
As far as the possibility that your carb'ed engine is getting worse MPG from shutting off and restarting, it's definitely possible. The accelerator pump is designed to prevent hesitation, but it also squirts a big (up to 50cc with a V8 engine) shot of gas everytime you depress the gas. With that said, there are guys that have used EOC with carbs and improved their mpg. As bestclimb mentioned, there is a risk that shutting off the engine, particularly at any speed higher than an idle, will allow gas to continue to be pulled through the carb what the pistons finish cycling on momentum and that gas can dilute and wash down your oil from the cylinders. If you turn the engine off at 2500rpm, I can see a problem, but at an idle I see it as far less of a concern.
|