rotax 912 - fuel in fuel tray

[johnm]

Boffins

 

with a rotax 912 (about 700 hours) - high wing aeroplane - with the fuel cocks left on .............. the passenger side air cleaner is saturated with fuel (over say a 2 day period) and there is a small quantity of fuel on the fuel tray

 

this leads to a rough start - lots of fuel one side - not the other

 

have replaced the internal horizontal float pins and the rubber seat valves - but problem still persists (might need a closer look at the seat valve again)

 

is there any other reasons for fuel on the fual tray ?

 

thanks

 

 

[facthunter]

Usually the float needle seat. There could be sediment in the fuel that is affecting the seat. Fine filters can help there but they can block. How level is the carb when the plane is parked? The only sure way to prevent this is to turn the fuel OFF. ( Then you must make sure to turn it ON, later) Nev

 

 

[johnm]

thanks FH

 

we'll bore in on the seat and will check level in the hangar

 

 

[Spriteah]

Thats a very interesting problem. Please keep this thread updated so we all can learn from your issue. Jim

 

 

[johnm]

problem fixed ! .......................... and 'lil old motor runs smooth

 

as facthunter suggested - it was the seat - photo is underside of the top portion of carb - the circular brass thing is the seat

 

cleaned / lapped ? all this up - valve now seals against the seat

 

why did the rubber seal and seat leak in the first place - don't know

 

what caused the scratches on the seat - don't know (at attempt 2 a cotton bud was used to lightly clean the seat)