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Leaking fuel from rear carb
Posted: Sat Mar 19, 2022 4:23 pm
by 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
Re: Leaking fuel from rear carb
Posted: Sat Mar 19, 2022 4:30 pm
by Bingo
Bingo wrote: ↑Sat Mar 19, 2022 4:23 pm
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
Re: Leaking fuel from rear carb
Posted: Sat Mar 19, 2022 5:35 pm
by 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 2739 times
Needle & seat.
- SU Carb Diagram.jpg (66.2 KiB) Viewed 2739 times
Re: Leaking fuel from rear carb
Posted: Sat Mar 19, 2022 5:50 pm
by 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.
Re: Leaking fuel from rear carb
Posted: Sat Mar 19, 2022 6:10 pm
by Glyn Ruck
Absolutely if it's light corrosion. If it's dirt you really need to get it out.
Re: Leaking fuel from rear carb
Posted: Sat Mar 19, 2022 7:04 pm
by 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
Re: Leaking fuel from rear carb
Posted: Sat Mar 19, 2022 10:56 pm
by Bingo
I ordered new floats, float needle valves, gaskets.
Re: Leaking fuel from rear carb
Posted: Sat Mar 19, 2022 11:54 pm
by 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!
Re: Leaking fuel from rear carb
Posted: Sun Mar 20, 2022 8:44 am
by Glyn Ruck
Remember to centre the jet properly.
All in Blue WS Manual.
Re: Leaking fuel from rear carb
Posted: Sun Mar 20, 2022 7:20 pm
by 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.