Float stuck

[boeingdrvr777]

Got a new Continental w670 but came out one morning to a puddle of gas on the floor. New engine. Plane has been sitting for a month. Gas poured out of bottom of #4 cylinder and bottom of carb and gascolater. Wondering if I should pull carb for repair? Thinking the shutoff valve was stuck causing fuel to leak past float etc. any thoughts appreciated.

 

[MiTasol]

Fuel should never get past the float valve and should never be showing on gascolator so my first question would be what sort of fuel did you use and what sort of gaskets were fitted to both the carb and filter. I suspect that the fuel is not compatible with the gaskets. The other option on the carb is dirty fuel holding the float valve partially open.

 

[boeingdrvr777]

Fuel should never get past the float valve and should never be showing on gascolator so my first question would be what sort of fuel did you use and what sort of gaskets were fitted to both the carb and filter. I suspect that the fuel is not compatible with the gaskets. The other option on the carb is dirty fuel holding the float valve partially open.

100 LL. Gaskets I don't know about. I took out the filter on gascolater and it was clean. There was fuel coming out of the throttle arm and when I pulled the prop thru gas was coming out of the exhaust pipe on #5

 

[MiTasol]

have a hard look at the gascolator gasket - is it smooth and firm or has it gone soft or show other signs of deterioration, cracking, foreign matter that stops it sealing?

Fuel out the throttle arm and going through the induction system shows the float valve is leaking and puddling in the induction trunk feeding the carb. That should never happen either as the induction trunk leading to the carb should have a drain hole to prevent the fuel collecting let alone the level getting that high. Have a licenced/certified maintenance technician who has radial experience look at the whole system as fixing the carb will not fix the other problems that clearly exist.

What sort of airframe is it in?

 

[boeingdrvr777]

have a hard look at the gascolator gasket - is it smooth and firm or has it gone soft or show other signs of deterioration, cracking, foreign matter that stops it sealing?

Fuel out the throttle arm and going through the induction system shows the float valve is leaking and puddling in the induction trunk feeding the carb. That should never happen either as the induction trunk leading to the carb should have a drain hole to prevent the fuel collecting let alone the level getting that high. Have a licenced/certified maintenance technician who has radial experience look at the whole system as fixing the carb will not fix the other problems that clearly exist.

What sort of airframe is it in?

On a stearman

 

[MiTasol]

Dusters and Sprayers will probably know a good A&P in your area if you are in the US.

 

[gumbyk]

I've heard of floats filling with fuel and sinking (brass floats), or disintegrating (if its synthetic) which could be the problem. There is a SB out for Marbel Schebler/Precision carbs to remove foam or hollow floats.

Best to talk to someone who knows more detail, and can interpret mod/AD/SB status to know what has been done to the carb/fuel system.

 

[MiTasol]

Thanks for that Gumbyk

As post #1 said new engine I took that to mean newly overhauled which should mean all ADs complied with so I did not include that. Obviously if the engine was never overhauled or overhauled in antiquity it is a very valid diagnoses.

If a prohibited float is the case the owner should also have a qualified AMT review the AD status of the complete engine including all other accessories and ancillaries. The lack of a drain hole in the induction strongly suggests there will be more problems.

 

[gumbyk]

Thanks for that Gumbyk

As post #1 said new engine I took that to mean newly overhauled which should mean all ADs complied with so I did not include that. Obviously if the engine was never overhauled or overhauled in antiquity it is a very valid diagnoses.

If a prohibited float is the case the owner should also have a qualified AMT review the AD status of the complete engine including all other accessories and ancillaries. The lack of a drain hole in the induction strongly suggests there will be more problems.

Missed the 'new' part. But, saying that, I've seen new parts fail. Just takes a marginal solder joint.

 

[boeingdrvr777]

Thx for all. We are taking the carb off and to a reputable shop here to make sure it is fixed

 

[FLYBOYJ]

I've heard of floats filling with fuel and sinking (brass floats), or disintegrating (if its synthetic) which could be the problem. There is a SB out for Marbel Schebler/Precision carbs to remove foam or hollow floats.

If I was a betting man I'd put my money here...