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I have my 50 Super in a shop for some tranny and gas tank work.  It’s been there awhile and he calls and says my battery is not holding a charge.  So I go get a warranty replacement of my 17 month old battery and I put it in.  I depress the accelerator and hear this loud noise (one of my manuals says clattering) and when I get off the accelerator the engine keeps turning but doesn’t catch.  It doesn’t quit turning until I put the key in the off position.  That kind of freaked me out because I’ve never seen this after owning the car for 45 years and I didn’t know if the wires were going to fry or what.   

 

My first thought was could it be the solenoid on the carburetor (the guy just rebuilt the carb) but its been running fine since.  Also when I put in the new battery, I wasn’t happy with the positive cable and intend to change it.  It’s tight, but I cant crank the clamp as tight as I want as the square end of the bolt wants to spin.

 

After a couple try’s,  the car finally started more than once, but would still do this clattering thing occasionally and then also not start.

 

So,  is it a low new battery? A bad solenoid on the carb? Or a bad positive cable?

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The piece on the carb should be a switch, and the solenoid is the part piggy backing on the starter. You may be having a problem with both. 

 

On occasion my switch on the carb will do what yours did. Start the starter when stepping on the accelerator  but not stop when removing foot from the accelerator.  But then it will work right most times.  I just toggle the switch to either Lock or Off position. 

 

The chatter you are getting could be the battery cable situation.  Although the square end of the bolt slips it may be possible to catch that with an open end wrench to tighten the terminal. I am assuming you cleaned the inside of the battery terminal when changing the battery?  If not I would do so now. 

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Thanks John, I did clean the post and cable end but when I go back there I will do it again and have a better wrench to lock it down more.  When I get it all diagnosed, I will also order a new cable just to eliminate any future problems.

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You described a solenoid sticking which is due to a low voltage condition.  Be sure all cables, connections and grounds are good.  It may even be due to defective starter relay if equipped.  Also 6 volt batteries are slow to charge:  12-24 hours with most chargers.

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Cleaning the battery cable is a double edged sword. While it is important the cleaners that scrape the insides and terminals will remove terminal materials. Thus it could be that excessive cleaning results in cable ends or terminals that have excessive clearances for the cable end to clamp the battery posts. It is also possible to remove some material from between the open end of the cable terminal so it will have more space to clamp but then you have to watch for the terminal bending too far and breaking.  

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The Buick accelerator starting system has a switch on the carburetor, a relay usually on the firewall, and a solenoid on the starter.   From your messages I suspect that the carburetor switch is OK.  The relay may be chattering but if is loud it is likely the starter solenoid on the starter that may need service.   Sometimes they can stick in the start position and then the starter will continue to crank the engine; you determined that you have to move the key switch to OFF to overcome this problem.

Check all grounds, all your positive cabling in the starter circuit and then remove the solenoid to rebuild or replace it if it is obviously not in good condition.  It is also possible that the relay may be sticking but in this case the engine would continue cranking but unlikely to have a loud chatter.

Good luck.

Joe, BCA 33493

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4 hours ago, Joseph P. Indusi said:

Check all grounds, all your positive cabling

Checking electrical wiring when you only have 6 volt potential really means undoing all connections and cleaning wire ends and posts.

My '53 Buick would cut out occasionally at speed on the highway.  After much checking I found a tiny bit of corrosion on one ignition coil primary wire.

My '30 Pontiac would do the  same thing and it was a tiny bit of corrosion on one ammeter connection.

Good Luck

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Thanks for everyone’s suggestions.  I eliminated the bad ground cable issue.  I took it off, spread the terminal and reconnected it and made sure it had a connection I was happy with this time.  Then, again, I turned the key on and it turned over before I pressed down on the starter pedal.  I talked with Doug Seybold and he said when they rebuild a carb, they always do over the switch on the carb as  well, saying it sometimes gets debris in it.  We will try that next.  I read the manual on the vacuum switch and can believe how dirt could mess it up.  Several times I held the pedal down and the engine started each time,  even after the sticking problem.

 

So my thoughts are this;  if it starts several times, low voltage Is probably not the issue.  So I think the battery is okay. That probably rules out a bad solenoid as well.   Something is causing it to energize as soon as you turn the key to the on position.  As soon as you turn the key on, there is power to the system.  I see the fan blade turning, and then when you press the accelerator down, the starter goes faster and the engine catches.  Joe P said there is a relay probably on the frewall.  I will have to check it next, along with the carb switch.  I let you know how it goes

 

 

 

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I did not understand from your prior posts that the starter operates when the ignition switch is turned on.   This would definitely indicate a problem with the carburetor switch.

The relay on the firewall is activated by the carburetor switch and the pull in coil gets +6 volts from the carb switch and the other end of the coil gets -6 or ground from the GEN or ARM terminal of the generator.   This is because when the generator is not turning the ARM or GEN terminals are at ground potential. When the coil is energized the points close on this relay and send +6 to the solenoid allowing the starter to operate.   Once the engine starts these generator terminals have about +6 volts on them and the relay coil does not have enough magnetism to. hold the points closed therefore the relay points open and do not supply +6 to the starter solenoid thereby stopping the starter from operating.

I think you are getting close to resolving this problem.

Joe, BCA 33493

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Thanks Joe.  I will show your post to the guy who owns the shop where my car is.  Though I have been in the BCA for decades, I have never had first hand experience of the carb switch malfunctioning, nor known anyone who has.  I’ve just seen a lot of cars over the years where someone ruined a perfectly good dash by punching a hole in it to mount a button that would bypass the carb switch.  That’s not going to be me.   It took a little bit to figure out the progression of how it was going wrong, but after talking to you guys and reading the manual over a few times, I’m beginning to understand it.  Hopefully we can give the carb switch a work over and make sure there is no debris in it, from when the carburetor was cleaned.  Hope to find out next week.  I’ll be back with a progress report.

 

Phil Taylor. BCA #7103

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Have you found the starter relay?  Contacts can stick and cause cranking anytime the key is on.  High resistance at the rivets inside will result in less than optimal voltage to the solenoid causing those contacts to stick causing cranking without input and even cranking after running.  I usually go to the carb switch first, but seldom find a problem there...it is usually the starter relay.

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Thanks O.T.  We will check that out.  I won’t get back to the car till next week.  Every thing

was fine until We had the carb worked on.  They test drove it several times and all was good.  But the guy told me it wasn’t holding a charge.  So I got a new battery.  Do you think that relay could be sticking even with the ignition switch in the off position causing the battery to run down?  I think we are zeroing in on it.

 

Phil


 

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Easy to test if the carb linkage is out of adjustment.  Remove wires from carb starter switch.  Using multimeter or test light, with the throttle closed, there should be no continuity between the terminals on the switch.  Open the throttle, and there should be continuity.  The service manual describes how to adjust the linkage to get the right clearances for the switch to operate properly.

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You can bypass the starter switch on the carb with a jumper wire between the terminals, which should either confirm it's the problem or remove it from the list of suspects. You could even install a momentary switch or button under the dash and connect the two leads from the button to those two terminals and start it that way for a while to see if the problem continues. That way you'll know if it's the switch or something farther down the line.

 

Everyone else has good advice here and there are only two or three possibilities, so work through them one at a time and see what happens.

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  • 2 weeks later...
On 9/29/2020 at 11:17 PM, Century Eight said:

 

Thank you all.  We will go down the list and try to eliminate the problem and keep you updated.

I don’t have the car back yet because the shop is still working on the transmission (waiting on parts) but the mechanic working on the car tells me he has started the car many times and it is now starting normally and has not messed up.  He cleaned the carb starter switch and that seemed to do the trick.  There must have been slight debris in there that came loose from when the carb was disassembled .   I will try it several more times and let you know if there are any more problems.  If that’s it, and I’m sure it is by everyone’s comments, I don’t know why some many cars had their switches bypassed and buttons installed, thereby ruining good dashes when it was the easier fix.

 

Thanks everyone so much for your input.  It certainly helped to zero in.

 

Phil Taylor #7103 

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