I have a Gamefisher (Force) 9.9hp 2 stroke, '94 model, which is not running. It's in very good condition but doesn't start or run properly. I can get it to start if I add some Seafoam or carb cleaner in the carb air intake but it will only run for a few seconds and then stop. I have two gas tanks and it doesn't seem to make a difference which I use. The gas is less than 2 months old and has Stabil added (in addition to the proper oil mix). I've been expecting the next step is to disassemble the carb and clean it but seeing that it runs, albeit briefly, when "fuel" is added to the carb I'm wondering if it might be something other than the carb. The various tubing appears to be in good condition, I don't see any indications of fuel or air leaks. Any suggestions?