Weber 45 DOCE 9 - Throttle Plate

[GV Z Car]

Wondering if I should be concerned with this...

I am setting up the 45's on a canon manifold. This model of Weber (45 DOCE 9) does not have a Progression Hole inspection port and hence I am confirming the location of the throttle plate and progression holes prior to mounting the carbs to the intake manifold. I have noticed on one carb that the return spring (and location of the throttle plate) is a little bit" lazy", as the throttle plate will still allow for one progression hole to remain uncovered unless I apply a small amount of pressure to the throttle plate spindle. I do not have this issue with the other two carburetors.

I am wondering if I should be concerned about possible on issues once I do eventually fire this thing up? Any thoughts are appreciated.

[240260280]

Good thorough checking!

This problem is common on used carbs.  The cause is usually due to three items:

1. Usage may have caused the shaft or plates to eventually migrate or wear from their original settings and binding of the shaft or plates is occurring.

2. Usage, manufacturing variance or proximity to heat  may have caused the return spring to weaken more than the other two.

3. Incorrect setting of push rod linkage settings such that it over extends the max range of the throttle plate at WOT and twists the main rod in the carb. body.

Solutions:

• It is good practice to refresh a used carb. by replacing the return springs. I believe they are in the middle compartment in a 45DCOE. Often there are alternate springs that are stronger.
• Releasing and tightening the side nuts may alleviate any binding in the main rod.
• Releasing and tightening the throttle plate screws may alleviate any binding of the plate against the throat.

[GV Z Car]

Thank you sir, yes on the 45's I believe they are in the middle compartment....linkage is not attached at this time as I am going through that as well. Thought perhaps if I attached a return spring to the problematic carb that might also alleviate this potential issue.

[240260280]

Yes, many use springs on the linkage to help close the throttle plates fully. Replacing the springs in the bodies is a best practice but you will have to remove the plates and rods to get at them. This may open Pandora's box. (It is easier to do on 40DCOE's).

Maybe you can open the central compartment and twist the spring or place a block against the spring end to cause it to provide more return pressure.

 

Here is SK Racing Carb that has similar spring mechanism as 45,50, & 55 DCO(E)

Edited May 1, 2017 by 240260280