Leaky carb, but where from?

[wellerchap]

Mikuni BS26 carb - leaks profusely once fuel is switched on...observing the leak suggested it was all coming out of the floatbowl gasket area (bought a new one, with other rubber washers/seals and needle), but upon close inspection of the photos I took it looks like the fuel is wetting the carb body, well above the floatbowl seal (see yellow arrow).

If a float needle sticks open, will it just leak out of the overflow stub at the very base of the floatbowl, or spew out further up, too?

The other pic shows shiny (wet?) carb sides, a big drip from the overflow stub and the puddle forming on top of the gearbox below.

Where's the issue likely to be?

[Simon Davey]

If the float sticks with the valve in the open position, it should come out of the overflow spout at the bottom, unless that's blocked. 

Then, it'll just flood the carb/engine. 

I'd put money on a fuel line leak further up, or the fuel tap, and that it's just running down to the carb body. 

[husoi]

It could well be a faulty float that can have a hole and isn't working anymore.

Or needing adjusted to proper height.

The float valve itself is not sealing properly.

Or as @Simon Davey says.

[wellerchap]

Thank you chaps - I'll be there tomorrow (son-in-law's) to put in the new seals, so will double check those issues then too.

[Hairsy]

Try to dry it completely (with the petcock switched off). Then turn the petcock on just for a second or two and try to spot the source of the leak.

 

I once spent lots of time trying to locate a leak like this and it turned out to be a fuel pipe above the carb that was dripping onto the carb and then down.

[wellerchap]

Seem to have sorted it - replaced the float bowl gasket for a new one (the old one seemed compressed in one corner, and flattish/hard)....no signs of the smelly, unleaded stuff yet!

Edited May 11, 2024 by wellerchap

[Simon Davey]

Good news