The saga continues......new carb, new coil, plug, changed oil and filter, set valves to .004 and .006, can throttle newly installed fuel cut off valve to reduce gas and engine seems to level off a lot. Light stumble then have to open valve to refill bowl....repeat. MTD motor 4P90JUA. Mfg says fuel problem.....no kidding. I have a small fortune in MTD parts in this beast....must be something simple....any ideas? Tighten or loosen valves? Carb #3? Unadjustable EPA carb or this problem likely would have been fixed by now. Not gas cap or roll over valve - checked them too. SEND HELP (Or parts)