Dear All,
I wondered if anyone has experienced this issue. I have an old MTD Pinto with a Briggs & Stratton 7hp OHV engine (Model: 121602-0275-E1). The problem is that when the engine is not running, fuel flows back through the carburetor (I assume it’s through the carb) and visibly pools at the bottom of the air intake assembly. This causes the engine to flood and prevents the engine from restarting. The leak is so bad that I’ve had to install a ¼ turn valve in the fuel line to prevent the entire fuel tank (gravity feed) from emptying whilst the mower is not in use. To start the engine again I have to close the fuel valve, remove the spark plug, turn the engine over to purge the cylinder, replace the plug then open the fuel valve very slightly to allow a trickle of fuel to the carb. Then i turn the engine over and if it starts, I have to open the valve quickly to prevent it starving. A ridiculous starting procedure!
My understanding of the issue led me to believe that either the carburetor needle wasn’t seating fully or that the float was filling with fuel and not lifting or was otherwise obstructed. So, I’ve replaced the needle and seat as well as the float and its pivot pin and all gaskets. I’ve also replaced the governor spring. On the bench the carb always works well. The needle is seating properly and preventing the flooding of fuel back through. When the carburetor is back on the engine, all tightened up and fitted with new gaskets, I get fuel leaking back again after the engine has been running.
The question is, am I missing something? Is there a known floor in these carbs when they warm up or a bypass / breather which is back flooding? Ideas welcome. I’ll update with photographs if anyone is interested.
I wondered if anyone has experienced this issue. I have an old MTD Pinto with a Briggs & Stratton 7hp OHV engine (Model: 121602-0275-E1). The problem is that when the engine is not running, fuel flows back through the carburetor (I assume it’s through the carb) and visibly pools at the bottom of the air intake assembly. This causes the engine to flood and prevents the engine from restarting. The leak is so bad that I’ve had to install a ¼ turn valve in the fuel line to prevent the entire fuel tank (gravity feed) from emptying whilst the mower is not in use. To start the engine again I have to close the fuel valve, remove the spark plug, turn the engine over to purge the cylinder, replace the plug then open the fuel valve very slightly to allow a trickle of fuel to the carb. Then i turn the engine over and if it starts, I have to open the valve quickly to prevent it starving. A ridiculous starting procedure!
My understanding of the issue led me to believe that either the carburetor needle wasn’t seating fully or that the float was filling with fuel and not lifting or was otherwise obstructed. So, I’ve replaced the needle and seat as well as the float and its pivot pin and all gaskets. I’ve also replaced the governor spring. On the bench the carb always works well. The needle is seating properly and preventing the flooding of fuel back through. When the carburetor is back on the engine, all tightened up and fitted with new gaskets, I get fuel leaking back again after the engine has been running.
The question is, am I missing something? Is there a known floor in these carbs when they warm up or a bypass / breather which is back flooding? Ideas welcome. I’ll update with photographs if anyone is interested.
