I've had a stubborn problem with my carburettor. I have replaced the seat and needle with an integrated, new unit after repeated flooding of the bowl. The fuel floods the bowl and then the engine chokes and dies. I have to wait till the fuel evaporates before I can start the car.

- Float is okay and sealed. Same symptoms with the previous float.
- Top gasket is rough and needs to be replaced.
- Needle and seat are okay. Same symptoms with previous needle & seat.
- Fuel pump is stock. But I have not checked pressure.

Any advice or ideas? The gasket is the only thing I have not replaced. Is this responsible for the flooding? I also have a regulator installed so I do not think the pump is the issue.

If I set float level to recommended level it floods at idle. If I over-adjust float to keep a less than half-full bowl it floods after about 10-15 minutes of driving.

What is the likelihood of the float jamming on the pin-hinge? (allowing the fuel to flood).

Perhaps I have a leak around the needle & seat?

Regards,

Chris

Is this a stock A12 carby DCG306?

If by "flooding of the bowl" you mean the fuel level seen in the sight glass is too high, that cannot be caused by a gasket problem. Its either a float problem, needle/seat problem, or excessive fuel pressure problem. Easiest thing to do is check the pressure, it should be under 2.8 psi.

Or do you mean the fuel level stays OK, but too much fuel is running into the carb throat? A common cause for that is a plugged air jet, allowing siphoning to occur.

Hi Dave,

Yes the fuel level in the sight glass goes up and beyond. When the car has stalled fuel is coming out from the top of the carb down the side. I can also see excessive fuel on the throttle plate, so it is getting way too much.

When I first adjusted the level of the float to reccomended level the fuel stayed on mark and then climbed to flood at idle.

When I over-adjusted the fuel mark was low in the bowl at the bottom of the glass, car ran well until 10 or 15 minutes and then proceeded to flood. Thanks for the pointers.

Carburettor is the autochoke version on the LWB, I think it is the 1980 model...

OK, carby is stock DCH306

Since flooding of the bowl means the fuel level seen in the sight glass goes too high, that is caused by fuel getting past the needle/seat.

Its either:
* a float problem, yes, float hinge can stick but not likely with the 306. Examine the pin for unusual wear

Or
* needle/seat problem

Or
* excessive fuel pressure problem.

I would check the pressure, it should be under 2.8 psi. In the interest of future reliability, I'd remove the external regulator, since stock fuel pumps have a built-in regulator.

Try this, put a fuel filter between the fuel pump and the carb. If this fixes the problem your fuel pressure is too high. If it doesn't fix the problem look at the needle and seat gasket it could be leaking fuel, or the needle and seat is loose.