Weber secondary throttle plate adjustment

[BDD]

I've checked and it does not seem that the secondary of my Weber 32/36 is ever activated. I never see signs of gas entering that barrel. When the rod with the ball joint is manually moved the primary opens and the secondary DOES open later. So the linkages work and are connected and do not bind, it's just that as the linkage is installed in the car, when pushing down the gas pedal there does not seem to be enough movement (or rotation of the rod with ball joint that is perpendicular to the firewall and which is that last rod to the carb.) to activate the secondary barrel.

The firewall grommets are in place. The passenger side one is new. It had to be sanded down a bit to get press fit in.

Here is my main question: Exactly what is adjustable to get the additional movement that is required to open the secondary throttle valve? Are the stock Opel linkages adjustable enough to get the secondary of the Weber to function?

I assume that when that opens, gas should then be pulled into the secondary barrel? I had earlier adjusted the float so that fuel should be properly metered and I have the correct jets installed per previous posts (all these jets).

[tekenaar]

Note the treaded/lock-nutted end link at the carb link below, that's what you would adjust for full secondary opening . . .



. . . I must add that I've never seen a GT linkage that was working correctly with the original Solex carb that needed adjustment for a Weber carb replacement!

FIRST!! . . . check inside for something under the gas pedal that would limit full pivot motion

[BDD]

My linkage seems to be a bit different. The adjustment in this photo seems to be at the large barrel shaped part in the lower left if the image. With mine there seems to be just the bent rod that passes behind the engine and a short linkage that connects it with the ball ended throttle rod that runs perpendicularly from this location to the back of the carb.

With my car there seems to be a threaded part of the rod at the opposite end, near the upper left part of the image where it links with the part that goes from the firewall to the pedal linkage. At this threaded rod there is a nut (maybe a jam nut to set a limit?) and a thin barrel that must be internally threaded. This barrel angles up and passes behind the engine.

To get more movement I would have to lengthen the bent rod that passes behind the engine? I suppose I would do that by moving the stop nut and placing a wrench on the threaded barrel part to lengthen the rod? I'd have to look at the car again to check that.

If this is done wouldn't it tend to rotate the rod with the ball joint and the pin that activates the carb throttle linkage? If so, I guess that you might also have to re-adjust that so it rotates to a new starting point.

Unlike the Manta the GT pedal doesn't seem to be very adjustable. The only thing I see after a quick look that could limit pedal movement would be the carpet and maybe some padding at the firewall. Maybe that's the issue. Does the carpet normally extend under the top of the pedal at the firewall?

[GTJIM]

The right-angle bit that sticks out behind where the "carb throttle ball" is fits into a slot in a steel pressing that bolts on to the carb throttle spindle. This slot and the bit that goes in it tends to wear - check that is a snugg, sliding fit.

Simply lengthen the rods does not alter the travel much - to increase travel all 'slop' needs to be eliminated and if still not enough then leverage ratios should be changed.

[tekenaar]

Originally Posted by GTJIM The right-angle bit that sticks out behind where the "carb throttle ball" is fits into a slot in a steel pressing that bolts on to the carb throttle spindle. This slot and the bit that goes in it tends to wear - check that is a snugg, sliding fit. Simply lengthen the rods does not alter the travel much - to increase travel all 'slop' needs to be eliminated and if still not enough then leverage ratios should be changed.

If slot wear at "pin" is enough, slip a short piece of vacuum hose over the throttle "pin" to remove slop . . . I actually have used a short piece of 1973 return fuel line (smaller ID than feed line) - hard plastic/nylon!

[BDD]

There is not much wear where the pin goes through the slot just behind the carb.

I have the red passenger side throttle firewall grommet in place, the drivers side one seems to be metal and is also in place. I'll check for slop from other causes.

Where the bent rod from the gas pedal exits the firewall and enters the engine compartment there are 2 places to connect it to the rest of the linkage. One of these mounting holes is lower than the other one. Mine is connected at the upper location. Is this the one to use for max. pedal movement? The upper one might raise the pedal further before depressed thus giving it more room to move but it also probably puts less movement into the linkage because of the geometry (leverage ratio?) of that part of the linkage.

Maybe the carpet is the problem because the secondary is only supposed to be fully opened when the pedal is 1/4" to 1/2" from the firewall.