starter continues to run! advise?

[Frank Tedesco]

Hello everyone. My Buick is a 47 Special with the 248. I transferred the carb starter switch to a rebuilt Stromberg AAV-16 carb and installed it on the car. I cranked engine the without coil wire to fill fuel filter and carb. The starter engaged and disengaged correctly while doing this.

I should note that the switch was giving me trouble on the previous carb. It would intermittently not complete the circuit to engage the starter. I would simple bypass it with a jumper wire. I did this for the first start with the new carb installed.

The car started right up but revved really high. It also sounded like the started did not disengage. I shut it down in a hurry. My service manual describes three things that should prevent this: Manifold Vacuum, generator voltage and mechanical lock out in Vacuum switch. Can someone point me in the right direction? Sorry for the long post.
Thanks, Frank

[Pete Phillips]

If you have by-passed the new starter switch with a jumper wire, that is your problem. The starter will constantly engage. Don't by-pass it.

Pete Phillips

[JPIndusi]

Buick engineering, for the time, was ingenius in developing the accelerator actuated starter system. Here is what I understand about it.
There are basically two subsystems to prevent the starter from operating once the engine starts.
With the engine off and not running the ignition switch is turned to the on position. This sends current through to the starter switch on the carburetor. When the accelerator pedal is depressed it allows a plunger with a contact spring to complete the circuit sending current to the relay on top of the starter motor. This relay is not the heavy solenoid plunger that engages the starter drive and actuates the starter. This relay has a set of contacts that complete the circuit to engage the heavy solenoid. This relay has a coil that energizes a small armature to close the contacts to engage the heavy solenoid. The coil now has +6 volts on one side and it gets ground to complete the circuit by being attached to the ARM or GEN terminal on the generator or regulator. It gets ground potential because when the engine is not running the armature is at ground potential. At this point , the heavy solenoid engages the starter and the engine starts.
Now here is where the two subsystems come into play. Once the engine starts, mainfold vacuum from the base of the Stromberg is routed through drilled passages to move a small disk that stops the starter switch plunger from moving to complete the circuit even if the acccelerator is depressed. This is the first subsystem.
Next, once the engine is running, the armature of the generator is no longer at ground potential but is roughly at +6 volts so the coil on the little relay now has 6 volts on both sides and so it cannot pull the little armature to close the contacts to actuate the stater solenoid.
What can go wrong?
First, from my experience, is that the carburetor base gasket may not have all the holes in the proper place and may partially or fully block manifold vacuum from reaching the switch on the Stromberg. Next may be improper adjustment of the switch or actuating plunger on the carburetor linkage. The shop manual gives details on adjusting the switch on the Stromberg. The other problems involve the starter relay on the starter motor. It may be defective or wired incorrectly.
Good luck.
Joe, BCA 33493

[old-tank]

As always Joe has a good description of the starting circuit. Even if the the vacuum switch is malfunctioning or there is a jumper wire in place the starter motor should not continue to operate after the engine starts. Other things that can cause the starter to operate after the engine starts is sticking solenoid contacts. This is almost alway caused by a low voltage condition such as weak battery, undersized cables, resistance in the ignition switch or starter relay (if equipped). (On 12v cars with a ballast resistor that is bypassed during cranking the engine will continue to run and the starter operate even with the ignitions switch off).
Frank, this is all probably too much information. First thing to do is go back to the last thing you did to create the problem.
Willie

[Frank Tedesco]

O.K. Retracing my steps...The carb starter switch worked intermittently on the old carb. I bypassed it when it didn't work, but never experienced this issue. I took some digital pictures of the internals before removing the switch from the old carb. Upon disassembly, I noticed the timing washer had moved slightly past the groove on the (bakelite) cam. When reassembling on the rebuilt carb, I MATCHED the timing washer with the cam. This may be where the problem lies, since I changed the timing from what it was previously.
I removed the cam assembly from the switch and used a jumper wire. The car started and the problem did not occur. I think I'll tune the carb since I really want to get back on the road, then I'll reassemble the switch and try to test the low voltage suggestions too. Thank you everyone who responded.
-Frank