Weber idle hang up

[djone101]

Any suggestions on this one?

When warm my idle speed hangs up but I can bring it down purely by applying load (i.e. lifting the clutch pedal) and then it will stay down.

My guess is that it's vacuum related - somehow preventing the throttle plates from closing completely - I've checked out the linkage and throttle spindles as well as possible - not easy since it all runs under the carbs - and lubricated all pivots with no effect. I'm running extra return springs too for competition so there should be enough force to close...

Any ideas or is it a carb's off job?.......

[papajam]

Hey Dave,
Had this same problem on my '68 a little while ago.
Assuming that the added throttle return springs are completely closing the throttles (are they?), and the carbs are properly adjusted, one check and one adjustment cured the problem. Using a timing light, check that the distributor advance is not hanging up or advancing too soon. Mine was OK so I kept looking. I ended up retarding the intake cam by 3 holes and advancing the exhaust cam by 3 holes. Don't know if the cam timing was the cause but it sure cured the hanging idle problem. And the car runs like stink at high revs too

[djone101]

Thanks Jim, haven't looked at the distibutor in a long time so it could be the advance mech. Cam timing has never been altered in the last 10 years so I don't think that would be it. I'll take a look at the weekend.