68 911 Tuning Question

[ipnetwrx]

I have a 1968 911 with stock carbs
40 IDAP 3C/1 I have verified all jets to be stock size.
Distributor is Bosch centrifugal advance.
Engine is stock as well.
When tuning the engine everything seems fine, idle is stable and carbs sychronized with synchrometer. When I test drive the car the engine idle races after putting the engine under a load. With no load this does not happen.
Where should I go first?

[EarlyPorsche]

The timing is 100% spot on? Vacuum advance is hooked up with a new hose?

[ipnetwrx]

This is not a vacuum advance distributor.
Point gap was set on the bench then the distributor was installed.
Timing was set with a timing light.
Should have stated that in the first post.

[911quest]

Make sure the throttle plates are coming to a complete close when they return to idle.

[Mo_Gearhead]

1. Be certain your accelerator pedal is not getting hung up in the carpet.

2. Check to be sure the throttle rod (in the tunnel) is not hanging up on something and causing engine RPM to speed up.

3. Hand throttle (plastic piece in tunnel can break) can hang/foul up also.

4. May need to raise car, unhook carb. linkage and check all throttle linkage movement from pedal ...to rear.

[911pcars]

Originally Posted by Mo_Gearhead

1. Be certain your accelerator pedal is not getting hung up in the carpet.

2. Check to be sure the throttle rod (in the tunnel) is not hanging up on something and causing engine RPM to speed up.

3. Hand throttle (plastic piece in tunnel can break) can hang/foul up also.

4. May need to raise car, unhook carb. linkage and check all throttle linkage movement from pedal ...to rear.

+1
Temporarily disconnect the throttle link at the engine bulkhead, then operate the throttle linkage by hand at that location or at the carb. Does engine rpm return to normal idle speed? If so, the linkage requires adjusting or is hanging up somewhere between pedal and carb link.

Sherwood

[ipnetwrx]

Thanks everybody for the assistance.
It was the throttle linkage in the tunnel.
Sometimes you can't see the forest through the trees......