Leaking fuel from rear carb

[Bingo]

Advice needed on diagnosing fuel flowing.

When I turn on the ignition, before starting the motor, fuel is flowing at an excellent rate from the bottom of the rear carb, not from the float pot overflow. I cleaned the float pot and added pot oil to no avail.

Looks like removing the air intake is troubling since access to the 4 nuts holding it in place to the front of the carbs is restricted.

Thank you,
Jim
64 s type

[Bingo]

Advice needed on diagnosing fuel flowing.

Weather has turned to pleasant temps so it’s time to prepare the jag for the season drives.

Unfortunately when I turn on the ignition, before starting the motor, fuel is flowing at an excellent rate from the bottom of the rear carb, not from the float pot overflow. I cleaned the float pot and added pot oil to no avail.

Looks like removing the air intake is troubling since access to the 4 nuts holding it in place to the front of the carbs is restricted.

Thank you,
Jim
64 s type

[Glyn Ruck]

It is likely that there is dirt in the needle & seat of the carb bowl. Fuel will the run in a constant flow through the drain tube from the centre of the float bowl & onto the ground.

Remove the float bowl lid (centre bolt) check filter and needle & seat for dirt. You might have to replace the needle & seat with a new Viton tipped needle .

Set your float level & close up & your problem will be gone. This is an HD8 but the same applies to an HD6

HD8 Carbie1.JPG (461.6 KiB) Viewed 1153 times

Needle & seat.

SU Carb Diagram.jpg (66.2 KiB) Viewed 1153 times

[John Quilter]

Sometimes a good rap with the handle of a screwdriver on the bowl cover bolt will free up a sticking float needle valve.

[Glyn Ruck]

Absolutely if it's light corrosion. If it's dirt you really need to get it out.

[Bingo]

I cleaned out the pot valance and removed and cleaned the needle.

It did not help.

Seems to me the fuel is leaking from the bottom of the Carb.

Seek pic.

Jim

[Bingo]

I ordered new floats, float needle valves, gaskets.

[Glyn Ruck]

Replace 4 the diaphragm in the picture above, Do both carbs while you are about it. If one has gone the other will follow.

Good luck!

[Glyn Ruck]

Remember to centre the jet properly.

All in Blue WS Manual.

[John Quilter]

If you suspect dirt in the carb, pull the float bowl cover, extract the float, suck out the fuel, (turkey baster) and have a look at the bottom of the bowl for sediment. Dig it out but do not use a vacuum cleaner.