wont idle...

[markey b]

the standard car was fine, until i gave it a bootfull on sat night, and now it wont idle. have cleaned idle jet, removed carb and replaced bottom throttle plate and put in brand new mixture screw, and still the same, checked breathers and vac pipes and all seem ok, fitted new carb to manifold gaskets, still the same.

basically it hunts badly, drives fine but as soon as its on idle it hunts and cuts out, its doing my head in, anyone got any suggestions?

its completely standard by the way

[Os8472]

Had a thought about this fella, did this start after you reconnected the AEI vac pipe?

[markey b]

nope before, checked one way valves too, its probably something silly that i'm missing but its doing my swede in! :disagree:

[Os8472]

oh, bugger was thinking the AEI was stuffed

[markey b]

same here, although it looks brand new, and holds vaccuum, plus wouldn't make it idle badly and hunt

[James5]

Have you removed the carb lobster to see if it is dribbling down the venturi on idle??

Also take it you set the tappets correctly

[Jimmy_GTT]

I had exactly the same some weeks before, but my car is on EFI.
It was the tank ventillation. It was totally blocked.
Just take the cap of for a test.

[markey b]

Have you removed the carb lobster to see if it is dribbling down the venturi on idle??

Also take it you set the tappets correctly

havn't touched tappets as they are silent! yes took off lobster and fuel is splashing down on idle

[James5]

havn't touched tappets as they are silent! yes took off lobster and fuel is splashing down on idle


Bet you still got **** inside the carb.

Is it splashing down through the Aux venturi?if fuel is comming from the aux venturi then that tells you that the main circuit (rarther than soley the idle/progression circuit) is comming into life. It shouldn't be have you tried dropping the idle speed ? or it could be that the float level wants dropping, you could try an extra copper washer under the needle jet.

Check the following

1) Acc pump jet (sticky ball bearing) or pump jet seal leaking (as has been said)
2) Needle valve is partially stuck open/won't fully seal.
3) Enrichment block and/or 1st stage diaphragm(s), or needle, leaking fuel through, causing excess fuel to then be present/sit higher in the emulsion tube.

[markey b]

I had exactly the same some weeks before, but my car is on EFI.
It was the tank ventillation. It was totally blocked.
Just take the cap of for a test.

i'll give it a go, strange thing is it drives ok, little juddery but once it revs its ok.

vac test drops to -15 then goes up when it hunts

[markey b]

Bet you still got **** inside the carb.

Is it splashing down through the Aux venturi?if fuel is comming from the aux venturi then that tells you that the main circuit (rarther than soley the idle/progression circuit) is comming into life. It shouldn't be have you tried dropping the idle speed ? or it could be that the float level wants dropping, you could try an extra copper washer under the needle jet.

Check the following

1) Acc pump jet (sticky ball bearing) or pump jet seal leaking (as has been said)
2) Needle valve is partially stuck open/won't fully seal.
3) Enrichment block and/or 1st stage diaphragm(s), or needle, leaking fuel through, causing excess fuel to then be present/sit higher in the emulsion tube.

cheers james, i'll whip the carb off again tonight and get it surgically clean and make sure all u have listed is ok

the fuel is dribbling onto the butterfly when its running, mixture screw doesn't seem to make a difference fully in or fully out still hunts, and you need to set idle at about 2000 just to get it to tick over :cry:

[markey b]

thinking about it the bit on the end where the leak off pipe goes, was leaking when i got the car, so i replaced the diaphragm but it was slightly different and the spring sat on the diaphragm bit itself, recon its split it after some spirited driving? lol

[markey b]

little update,

carb off and stripped, cleaned and back together, loads better now just needs setting up properly :)