Author Topic: Carb issues me thinks (Read 1265 times)

gymark2002 · **on:** May 04, 2020, 01:52:01 PM

Hi,
Got a 1600 with twin Kadrons.

For some reason the buggy will not turn over unless I pour petrol straight down each carb, then it runs fine.

If I leave it for about 1 hour, I have to do the same again and stick petrol down the carbs for it to run.

I have done the normal checks of stripping each carb down jetting all the nooks and crannies and putting them back together.

I am taking the petrol from the fuel line and its fresh petrol.

Any ideas on what is causing it?

Doon L001 · **Reply #1 on:** May 04, 2020, 02:34:08 PM

Is this fuel pumping through ok?

Could be lines failing if not Ethanol proof, fuel filter blocked.

Dave

gymark2002 · **Reply #2 on:** May 04, 2020, 02:37:38 PM

thanks yep, will check my fuel pump, when I stripped the carbs down there was Fuel sitting in the bowls

snoopy · **Reply #3 on:** May 04, 2020, 04:51:26 PM

are the accelerator pump jets working?

pepsi81 · **Reply #4 on:** May 05, 2020, 02:16:41 AM

Perished accelerator diaphragm $:-\$

gymark2002 · **Reply #5 on:** May 05, 2020, 10:22:51 AM

Thank you for all your help,

I am right in saying if i take the carb off and pump the accelerator pump I should see a jet of fuel come out the pump injector nozzle?

I am seeing nothing so guessing as you have all said I got accelerator pump issue.

Out of interest is the USA the only place you can order replacement diaphragms from?

Paul1953 · **Reply #6 on:** May 05, 2020, 11:01:53 AM

you post re... fuel coming out of injector spout.....

I had major issue with a 34 Pict carb that had stood for a year. With a full float chamber and operating the throttle spindle nothing at all came out of the injector. Tried all sorts to get the two ball bearings that comprise the non return valve to move freely but couldn`t.

Farmer Bob came to the rescue and told me to bring a pan of water to a simmer, (just under boiling point), and "cook" for 30 minutes. Did this and the carb then worked as it should. I was surprised by the amount of greasy crap in the pan afterwards.

Don`t see why this cannot be done with any carb.

Replace diaphgrams, gaskets, o rings and the like for new as a matter of course....

snoopy · **Reply #7 on:** May 05, 2020, 11:22:43 AM

it may just be blocked jets pull them out and see if it squirts out of the gallery.

gymark2002 · **Reply #8 on:** May 05, 2020, 12:06:47 PM

I have sprayed carb cleaner in the holes on the pump chamber and it comes out the nozzle fine so i know that is not blocked.

I cannot see any holes in the diaphragm but when assembled and fuel is in the chamber I pump the accelerator arm and nothing comes out of the nozzle.

gymark2002 · **Reply #9 on:** May 05, 2020, 04:48:44 PM

I have ordered a couple of diaphragms from Germany hopefully that fixes the issue as i cannot see what else it could be
Will let know how i get on
thank you

farmer rob · **Reply #10 on:** May 05, 2020, 05:54:17 PM

Like Paul said, there are two ball bearings in the grillings, that work as one way valves and they work with gravity. These get stuck if it has been left standing. There is one before the diaphragm, so the diaphragm's suck lifts one ball bearing to suck fuel out of the float chamber, this ball then stops the fuel from getting pushed back. Instead the fuel gets pushed past the second ball bearing and out of the spry jet. this ball then drops down so more fuel can be drawn past the first ball.

If you have got a small piece of plastic pipe, like windscreen washers pipe. You can put this up tight against the two holes in the diaphragm chamber and suck and blow to see if these balls are moving and working as a one way valve but do keep the carb vertical as fitted to the car because these balls work on gravity. Tapping the carb with a screwdriver handle can get them moving or boiling them in a saucepan with water and a bit of washing up liquid has proven to work

Rob

gymark2002 · **Reply #11 on:** May 05, 2020, 07:08:02 PM

Cheers Rob,

Would they stop carb cleaner spray if blocked? (l know this is more high powered)

I sprayed carb cleaner down the hole in the pump accelerator chamber and it came out of the brass Nozzle, would this mean the balls are moving freely?

thank you

farmer rob · **Reply #12 on:** May 05, 2020, 08:42:56 PM

This is why you need to suck and blow down each passageway to make sure the balls are moving and sealing, otherwise you will have no pump action

Rob

gymark2002 · **Reply #13 on:** May 05, 2020, 09:57:30 PM

Thank you,
look's like i will be sucking and blowing tomorrow to see If can get them moving,
I did remove the Brass Nozzle and the little ball bearing out of the top and then put it back, did not realise there is one at the diaphragm end as well.

pepsi81 · **Reply #14 on:** May 05, 2020, 10:21:19 PM

Once is cool. Twice

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March 09, 2021, 06:45:46 AM

Carb issues me thinks