mowingmayhem;3397 I have tried putting gas in and leaving it on the patio to see if it would leak or where it was leaking from but have had no luck. [/QUOTE said:
By "no luck" do you mean that the fuel level hadn't gone down? If your mower can sit with a full tank for a week without the fuel level dropping then it's not leaking fuel either externally or internally.
If it's not leaking fuel it must be burning it. How does the engine run? What's the condition of the spark plug (is it sooty?)? Many walkbehinds use a carb mounted on the fuel tank and when the carb diaphragm goes bad the engine will run very rich. What brand of engine is in your mower?