I have a Honda horizontal shaft GC160 (http://honda-engines.com/Engines_owners_manuals/ownersmanuals/gc160.htm) that I just put on my tiller and whenever I lean it back a bit gas leaks from the 2 bolts securing the carb to the engine. The bolts are at the back of the engine (facing me) and each travels through the plastic piece that holds the air cleaner, then through the side of the carb and then entering the engine. There is a fair amount of gas that is leaking. I purchased the motor second hand from a dealer near me that assured me it was in perfect working order with only a couple hours on it. Is there anything that I can do to prevent gas from leaking?