RE: Choking an 813
Yup, the carb has an accelerator pump that squirts enough gas into the carb so to prime it. Only problem is that accelerator pump is not always reliable. Mine failed right away and took about 20 pumps to prime, then fail altogether. I switched to a 668 carb with a built in choke and never had any more problems.
While people that have working 813 carbs defend them, I have found them failing too often for me to be able to appreciate them.
Dennis