I use B12 in my small engines to clean out the carb. I am rehabbing a neglected Tecumseh float carb for my old Ariens snowblower. I stripped down the carb and put the pieces in a cleaned out glass jar with a lid. I added enough of my 2 stroke mix to cover. I shook the jar several times and quit for the day. Today, I re-assembled the carb using a spray can of house brand carb cleaner. There was a 1/2 inch of sludge on the bottom of the jar. I contemplated soaking the carb in B12, but the can was 1/2 full and I didnt feel like driving to get more.