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Fuel In Crankcase

There are two separate situations that lead to this problem, both of which are common to float style carb designs. Leakage During Transport This situation primarily occurs while transporting equipment from one location to another. During transport, the float bounces up and down inside the fuel bowl, allowing the inlet needle to become unseated. Fuel then moves through the car, without the engine running and enters the crankcase through the valve train. If not already equipped, install an in-line manual shutoff valve and turn it to the off position before transporting equipment. Static Leakage (while not in use) This situation occurs when trash or debris gets lodged between the needle valve and seat, allowing gasoline to continually flow directly through the carb into the crankcase. The first step in correcting this problem is to have the carb cleaned and/or rebuilt. Step two would be to make sure that a fuel filter is used to keep the trash out in the future and step three would include installing and using a manual fuel shutoff valve. **Note - It's a good idea to make it a habit to turn off the valve anytime the equipment is not in use. Defective Fuel Pump Diaphragm While not as common as the first two causes, there is a potential for fuel to be found in the crankcase on engines that use a vacuum style fuel pump. Because these types of fuel pumps operate by vacuum, a pin hole or tear in the diaphragm can allow a small amount of fuel to be drawn directly into the crankcase. Even with very small holes or tears, it doesn't take long for the oil to be severely contaminated. There are only two options that will correct this situation: 1. Rebuild the pump if the pump design and manufacturer will support this as an option. 2. Replace the pump.