su carb racing when accelerator pressed.

[Larry 1300]

Hi I rebuilt the single su carb on my Dolomite 1300 1.3. I had a bit of a problem with her not starting but that's ok now as I followed the advice on the forum.
When the car started she was racing so I adjusted the throttle adjusting screw and this stopped. I tried to tune the carb following the instructions I had from SU carbs. She was idling fine after this.
However the problem that I have is the when I press the accelerator the car races again and keeps racing until I manually push the cam lever assembly back by hand.
Before I rebuilt the carb the spring on cam lever assembly was very tight but it is not nearly as tight now.
I phoned SU carbs for advice and the dude said that I should check that the throttle disc is sitting correctly and that there is no air getting through when it is closed.
I will do that today and if you can think of anything else please let me know.

[Henk]

Had to replace the accelerator cable twice in 30000 km. Gets stiff (prone to heat?) and won't retract when releasing the accelerator pedal.
Undo the cable at the carbs end and turn the throttle linkage by hand to see if it moves back.

[Larry 1300]

Hi I took the carb off and readjusted the throttle disc like the guy from SU Carbs advised. The car started with choke but died soon after. The throttle is still sticking and causing the engine to race and I have needed to turn it by hand at the carb to stop it.
I undid the throttle cable from the carb side and the cam lever assembly seems to be closing ok when manoeuvred by hand.

Please let me know what play there should be on the throttle cable at the carb side and how to properly adjust it.
Please let me know if you think that the engine is racing due to the throttle disc, the accelerator cable or the piston sticking.

I have read Jonners article on tuning SU carbs and will be trying that method next week.

[Larry 1300]

Hi guys , any advice on the following please?

Please let me know what play there should be on the throttle cable at the carb side and how to properly adjust it.
Please let me know if you think that the engine is racing due to the throttle disc, the accelerator cable or the piston sticking.

I have read Jonners article on tuning SU carbs and will be trying that method next week.

[Jon Tilson]

You dont want a lot of slack on the cable but then you dont want it too tight so its affecting the idle.

With the cable detached you should get a smooth action of the rest of it and an easy return to the idle position. You want the
idle set with the engine warm and the ignition timing set at 10 BTDC IIRC on a timing light to about 750 rpm.

Adjust the mixture at 1000 rpm though.

When its all smooth you can check your cable is also smooth acting. Sometimes if you have a dodgy earth return the accelerator and choke cables can act as an alternate return path. Too much of that and they will overheat and melt the plastic sheath and get sticky. Also worth checking the pedal pivot points and return spring too.

Jonners

[davy67]

Hi Laurence, I finish my shift on Christmas Eve then I'm off on annual leave til 10th January, if you want me to take a run up to yours I'll be glad to be of help?

David

[Larry 1300]

Hi special thanks to David Harper who helped me solve the mistakes that I had made when rebuilding my carburettor.
I had not connected the springs on the choke lever or on the cam lever correctly. David came to my house to help.
All good now.