Packard Forum Index » Pre-War (1899-1942)

Debugging a 1929 640 Roadster.
Throttle does not return to idle and sticks at high speed.
Appears the 10" spring from the Carb throttle shaft to the car frame is not strong enough to return shaft to idle position. Does anyone know what the specifications for this spring are? #'s of force , material, Packard part #.
Any help would be appreciated.
Thanks,
Lou

I had a sort of similar problem on my '37 115. There was all kinds of binding in the linkage, and the previous owner threw multiple springs at the problem. Couldn't determine any of that with the springs in place though. Once I replaced the ball joints and sockets on the linkage and freed up a bent shaft, the original spring was just fine.

The throttle cross shaft uses two cheap aluminum bosses on the firewall that wear and inhibit proper action. Sometimes the rivet pins loosen as well and the thing develops slop.

The correct throttle spring is anchored to the driver's side floor board where there is a cast tang.

Added springs are an attempt to fix this problem.

I had the same problem with Billy Hirsch's car and it had under 25,000 miles on it. In that case he went crazy with chrome plating and the parts didn't go back together correctly because the original fit went out the window.

Thanks for the replies.
Do I understand correctly that there should be no spring?
See attached photos.
Thanks,
Lou

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Tim
I'm wondering if this location is visible in photos. I, too, am trying to fix "customized" things on Jepson's old Speedster, and I think the current spring location is not correct.

Thanks.

The spring shown in the photos is not original. There was no spring on the passenger side of the engine.

Tending to agree with Sherlock, I've got a few photos and 1 factory illustration on that side of a 640/645 motor, no such springs shown.

There is a lug on the LHS of the sloping aluminum floor. The return spring connects horizontally to this lug and the back of the throttle lever, see photo

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THANK YOU!!!

Thanks for the reply. You are correct this spring was added as a poor fix for the problem. I am attaching photos of the accelerator spring and a linkage from it down to the base of the steering wheel.This linkage is very loose and probably shot. What is it for? This seems to be part of the problem.
We cleaned and lubed the throttle shaft but it still hangs up.
What are the three screws on the carb. One seems to be an idle stop , not sure what the others are. The range of motion from slow to fast idle on the lever of the steering wheel seems to be no change halfway up then quickly rises to very fast. Is their a way to broaden the range? Looks like removal and cleaning of entire linkage and bushing replacement will be needed. Do any drawings of these linkages with part #'s exist. ? Thanks,
Lou

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