Small Engine Carburretor Problem

[paulrockliffe]

I've got a petrol ride-on lawnmower, it's got a Briggs and Stratton engine, 1.5hp or so, this afternoon the following tale of woe has curtailed my driving pleasure:

Lawnmower working perfectly fine. Stop engine to fill with petrol. Notice petrol leak from under the air filter. Remove air filter, petrol is flowing from the tank, into carb, up into air filter and then out onto the grass. Fuel supply hose removed and blocked with pencil, petrol drains from carburretor, but some remains in the filter feed pipe. Turn engine over to blow petrol out of feedpipe.

On inspection, the carburretor has a fuel inlet above a float-bowl, air inlet at the top, but also a vacuum pressure supply from the engine.

What has happened to let the fuel start flowing up through the air filter, any ideas?

Thanks

[catman]

in my past experience, flooding was caused by either a hole in the float, or dirt under the needle of the shut-off valve.

Tim

[Classic Grad 98]

If I'm understanding the question properly then I'd suggest a sticking needle (float) valve. Easy fix.

[SWH]

^^^ Agree.

This may help (it's bigger on the link) http://www.lawn-mower-shop.com/carb2.htm



A holed float can be fixed with araldite if necessary... and if it's just crud in the fuel it's a quick clean out.

ETA: A healthy tap on the float bowl can cure it if you're mid mow

[paulrussell]

Tap the side of the carb with the handle of a screwdriver. If the flooding is caused by a sticky needle then that might solve the problem.