Leaf Vacuum

[Ray1]

Today my leaf vacuum decided to let me down, Its fitted with a 3.5hp briggs and stratton engine, it started and ran perfectly for half an hour then i stopped it to empty the collection bag. When refitting the bag i noticed its leaking (i mean pissing out) fuel from the bottom of the air filter. I removed the filter and the fuel is leaking out of the carb, not the bowl, but out of the carb itself. I cleaned it all off and started it and carried on sucking up leaves, stopped to empty the bag and it started leaking again. Ive changed the needle as it looked worn and replaced the bowl gasket. Started her up and left it running for half an hour, no leaks at all, turned her off and within 5 mins its leaking fuel out again. Anyone got any ideas as its my most used machine at the moment and im not happy using while its leaking fuel.

[twistedhicap]

is the float ok ? sometimes they can get holes in and fill with fuel and not lift and shut the needle also its it all clean you say a new needle what was the seat like ?

[Ray1]

Ive blown until im red in the face down the fuel inlet with the carb turned upside down so that the needle is seated and it wont let any air passed into the fuel bowl so i assume the seat is ok, how do you check the float? ive visually checked it and all seems ok, there is no fuel inside it.

[twistedhicap]

usually can tell as ther eis fuel inside it ! hmmm interesting one !

[Ray1]

Its got me baffled aswell, pretty frustrated i cant work it out.

[GardenKit]

What is happening is that the needle is leaking either because of some dirt on the seat, or a damaged needle/seat, or as suggested, leaking float.

 

It is not leaking whilst running as its using the leaked fuel as fast as it leaks in, but when the engine stops the fuel fills up in the bowl and overflows into the carb throat, some will come out through the air filter, but depending on the angle, some may go into the inlet manifold and through the engine into the sump.

Check your oil and change if diluted after first having cured the problem. Most likely a new needle and seat will do the job

[Ray1]

How do you remove the seat in the carb??? ive got the full carb repair kit and assume the little red round part is the seat but didnt want to start prodding around trying to remove it without really know what i was doing. Also what are the three round white sponge parts for?

[GardenKit]

Dont worry about the sponge bits, just hook out the red seat without damaging the ally around it. Gently push in the new one with a nice flat ended punch or similar.

[Ray1]

Needle seat changed and its still the same, its got to be the float, so new one ordered and fingers crossed.

[Ray1]

Still not fixed it, new needle and seat, new float. Put it all back together and left it over night on the bench and no fuel leaks at all, take it outside and start it up and run it for a couple of mins and fuel is leaking out of the air filter. So i clean up the leakage, leave it and go back a couple of hours later and there is no fuel leaking out, start her up again and fuel leaks out again.