I have a Troy-Built Honda runned 5.5 HP 160 CC lawn mower. It is new in 2006 and we've used only once. I added gas and can start the mower. It runs for about 3 minutes and then stops. The oil is good, full tank of fresh gas, tight spark plug cap. Any ideas?

Used once in two years, you probably have some gunk in the carb bowl. I'd remove the bowl and clean it, also test the needle valve by raising and lowering the float. This should start and stop a good trickle of gas. Reasseble and add a small amount of Sea Foam or other good carb cleaber to the tank.