Change In Return To Idle After Venturi Delete

[Lawrence Coppari]

I removed my venturi on my 1986 951 and piped it up as per usual. There is a difference in the engine speed as it returns to idle.

Before removal:
Rev up engine in neutral. Rpms return to idle just barely dropping below 900, perhaps 50 rpms, then returning to 900.

After removal:
Rev up engine in neutral. Rpms also return to idle of 900 but drop to 650 before returning to 900.

Any ideas why the change in operation.

[Paulyy]

did you hook the vaccum lines up properly?

[Lawrence Coppari]

[Lawrence Coppari]

I don't know why what I've written twice now is not posted along with the pix.

I removed the venturi and took a piece of copper tubing and connected the red dot to the green dot. The red dot is the end of the tube that comes from the intake plenum that partially obscures #2 spark plug. The green dot is the end of the line that goes to the braking system.

I then plugged the line with the yellow dot.

That's all I did. The small vacuum/positive pressure lines were return to their original locations.