What can this be? Last week when I flew, my engine (912UL, SN 4005199, 80hp) performed fine. A week later (today) in the hangar there was smell of fuel and tiny drips on the floor. Upon opening the cowl, and removing the air filters, inside each carb, fuel is leaking from one of the tiny holes facing the air filter, drenching the air filters (I can put my finger on that hole and feel the fuel coming out). What is odd is that suddenly both carbs chose the exact same moment to leak fuel exactly the same way while the engine is off (I think this point should tell a lot, but I don’t know what). No fuel is coming from the vent tubes; all fuel is going out the tiny holes facing the air filters.
I mention this because it may be the related. About 20 hours ago I did a complete 5-year rubber replacement. The new fuel pump tested at 5psi throughout the rpm range. The 1-3 floats weighed 2.90gr and 2.85gr, 2-4 floats were 2.92gr and 2.89gr. The fuel levels were correct. I ran the engine for 20 minutes and then cleaned out the float bowls. Everything was running smoothly and I flew for 20 hours.
Could it be that a piece of debris is clogging the fuel pressure bleed-off orifice; and when I shut down, the fuel pump just pressurized the lines and they remained so? But even then, why would fuel come out the hole facing the air filter instead of going out the vent tubes or being held back by the valves? Being a Rans S-7 tail dragger, the engine is canted backward considerably toward the air filter while on the ground.
When I last flew, I shut off the fuel valve (which does work to completely stop fuel, as noted when I remove the gascolator filter). I also fully topped off the fuel tanks (Rans S-7 – high wing) and put the plane away. I came out (as I have for the several months since the 5-year rubber) and this time both carbs were leaking fuel.
I’ve read all the forum results related to my issue but see no one mentioning fuel weeping out the carb hole facing the air filter. Do I take the carbs apart? Or do I run the engine, look things over, and go fly as if it fixed itself (?) and chalk it up to an unknown anomaly?
Thanks,
Dennis
I mention this because it may be the related. About 20 hours ago I did a complete 5-year rubber replacement. The new fuel pump tested at 5psi throughout the rpm range. The 1-3 floats weighed 2.90gr and 2.85gr, 2-4 floats were 2.92gr and 2.89gr. The fuel levels were correct. I ran the engine for 20 minutes and then cleaned out the float bowls. Everything was running smoothly and I flew for 20 hours.
Could it be that a piece of debris is clogging the fuel pressure bleed-off orifice; and when I shut down, the fuel pump just pressurized the lines and they remained so? But even then, why would fuel come out the hole facing the air filter instead of going out the vent tubes or being held back by the valves? Being a Rans S-7 tail dragger, the engine is canted backward considerably toward the air filter while on the ground.
When I last flew, I shut off the fuel valve (which does work to completely stop fuel, as noted when I remove the gascolator filter). I also fully topped off the fuel tanks (Rans S-7 – high wing) and put the plane away. I came out (as I have for the several months since the 5-year rubber) and this time both carbs were leaking fuel.
I’ve read all the forum results related to my issue but see no one mentioning fuel weeping out the carb hole facing the air filter. Do I take the carbs apart? Or do I run the engine, look things over, and go fly as if it fixed itself (?) and chalk it up to an unknown anomaly?
Thanks,
Dennis
