This one's weird even by '60 Buick standards. The car: stock '60 Invicta, 401, automatic, stock gas pedal start. The problem: the starter engaged itself w/engine already running. Details: While idling at a red light the starter suddenly engaged itself - you can imagine the noise. I was about a mile from home, assuming it was the trans I drove off and made it to my driveway. By then the starter had disengaged itself. Now all I get is gnashing gear teeth. I'm removing the starter today to check the damage. The starter & solenoid are rebuilt - maybe 20 starts since install. I'm familiar w/the carb starter switch and how it works, it was supposedly cleaned a year ago when the carb was rebuilt and has worked fine since, I don't see it as a prime suspect due to it's mechanical design. I also vaguely understand that the juice from the generator - while running - will prevent the starter from running. The solenoid relay is original. In 40 years of driving I have never experienced this. What would cause the starter to suddenly run all by itself?? Can solenoids somehow engage themselves?? Any help is much appreciated. Thanks.
First off, welcome to the forum. Hope you find your stay here a pleasant one. As for the starter circuit, although I've never owned a Buick having this design, I've always been fascinated with it. It's really a brilliant circuit and one designed to prevent the exact thing that happened to you. I found this simplified image of the circuit: I would double check all the components for proper operation. Even new components can fail. In a double fail-safe system like this I would look at the common item in the circuit which, when it fails or becomes weak, could cause the problem regardless of the rest of the system. That would be the spring in the starter solenoid. I've seen these fail and cause this problem on several non-carb start vehicles. HTH
I've seen it happen where all the teeth are shredded off the starter gear, and the flywheel teeth mostly gone. Hope yours is better than that.
Agree, except I would also check to see if the solenoid is being energized by 12v shorting to the start circuit. I've seen a Ford solenoid short internally, but not GM, so I would be looking for external shorting. John
Hey guys - thanks for everything so far. Starter removal is delayed so no update yet, will hopefully get to this in a day or two. In the mean time: Mosslack: I agree w/your diagnosis. I have an old, spare starter on my bench - last night I pulled the solenoid off and I see the spring you mention. By "failing" I assume you mean this spring would break, releasing compression on the lever arm which could allow the starter gear to slide out freely (without electrical actuation) and hit the ring gear, correct? Steeveedee & Cameo: Understood. Replacing the starter is easy enough, replacing that ring gear/converter is something else entirely. I will hope for the best. Nailhead: The dreaded short is my worst fear as I am not good w/electrical stuff. If it's not too much typing, may I ask how/where I would look for the external shorting you mention? Thanks again! Mike
Correct, it is rare, but it does happen from time to time. Being as you plan to remove the starter first, it will be very easy to check. And John's comment about external shorting is also a very real possibility. If you look at the diagram, what would happen if a live 12v wire was shorted to the 's' terminal on the starter solenoid? In that case all of the fail-safe's in the world would not keep that starter from engaging. HTH
...and possibly some well-meaning but ill-informed "mechanic" at some time in car's lifetime messed with wiring while trying to fix something...o No:
Update: I was able to remove the starter today. The starter gear teeth are ground clean off, about 1/4" in length from the end. The solenoid spring looks like new - no breaks or anything unusual - so I guess that's not the culprit. The ring gear teeth look good except the leading edges are chamfered just a tiny bit, and there's a tiny burr at the leading edge of the teeth as well. The cable from the battery and the 2 wires to the solenoid are old and tired looking but nothing too scary. Next: I'll have the starter rebuilt. In the mean time I'll have a look at, or replace, the starter relay - agreed? I'll think I'll also replace the battery cable and the 2 solenoid wires for good measure, just to eliminate any chance of shorts here. I guess I'll take my chances w/the ring gear - hopefully the new starter gear will mesh smoothly enough when the time comes. Mosslack: Thanks for suggesting the short to the S wire. That makes sense to me, even with my limited electrical knowledge, and it's another good reason to replace that wire. Anything else to check at this point? Thanks for the continued help and interest! Mike
X3. I pray that this is not the case. As was said earlier, with the Dynaflow, this would be a big deal.
Hi, Think I have all this right, but welcome any comments: Starter shouldn't need a total rebuild, just the drive replaced. Check the brushes for wear while it's out. Check you have the correct starter relay before replacing it, and if correct, check it cuts out the starter circuit when energized. If the relay isn't working, then the problem could be the carb switch. I'm not familiar with your year, but I believe carb switches uses engine vacuum to lockout the starter when running--whatever, verify it is functional. As for possibility of shorting 12v to the solenoid, what did you see when you removed the starter---is there any way the heavy cable from the battery could have been shorting to the wire to the S terminal? With the ignition key in the on position, engine not running, accelerator not depressed, check for 12v at the wire to the S terminal--should not be there--if it is, there is a short or carb switch bad or not adjusted properly. Check for continuity with an ohm meter or trouble light between the battery connection to the solenoid and the S terminal with all wiring disconnected. Should not be continuity. If there is, solenoid is shorted internally. John
I have the original starter from my '62 I'd let go relatively cheap if your interested. It worked perfect when I pulled it a few years ago. I think it should work in your '60. Just thought I'd throw it out there. PM me if your interested.
Friday update.... Cameo: Thanks for the offer but I have two starters already - the subject starter and another that came with the car. Both are now at the starter shop getting repaired as needed. Both are in good shape and not in need of a complete rebuild - will most likely only get new solenoids, new drive gears and a little clean up. Nailhead: I spent some time w/the volt meter and followed your advice. Nothing seems to be out of order, 12 volts seems to flowing when and where it should. The carb switch and relay seem to be working as they should. No obvious shorts. No obvious wiring faults where 12v could be sneaking on to the S wire. No continuity between solenoid terminals so no obvious shorts there either, not at the moment anyway. While this is generally good news the mystery remains as to what made the starter run. All agree that 12v hit the S terminal at the wrong time, but so far there's no obvious cause for that. So, I'm leaning towards the solenoid internal contacts: I'm thinking they shorted or closed due to some internal mechanical or electrical fault, and the starter ran until they let go. It's weak but it's all I got. I'll run this theory past the starter man early next week when I pick up the starters. Have a nice weekend...hopefully one that doesn't involve starters. Mike
As I said earlier, I never actually had a Buick with this setup so I am a bit curious. If viewing the diagram I included with an earlier post, the starter relay appears to be separate from the starter. If this is the case, are you actually talking about the relay having an internal short or do you mean a short between the 'S' terminal and the battery cable on the solenoid?
The drive gear in your picture is damaged from staying engaged.The solenoid spring that collapses is on the small plunger inside the cap,not the big one on the shiftfork plunger.A new solenoid should be on your short list.Ask for a high temp bakelite cap 132 turn coil one.:TU:
Even tho carb switch "seems to be working," I'd at least disassemble and clean...just in case there's some gum in there that could cause intermittent sticking...
65special: Yes, that drive gear was engaged for what seemed like an eternity but was really about 1 minute. Thanks for mentioning the smaller spring at the contact/cap end of the solenoid, I wasn't aware of this detail but now I'm wondering if it's the culprit here. If it were to collapse/fail could that cause the starter to run like it did? Mosslack: Thanks by the way for that schematic, it's been very helpful. Yes, the relay is separate from the starter - it's mounted up near the battery, next to the voltage regulator. As far as I can tell it's working OK - I can hear it open and close when it should. The short I'm suspicious of would be at the contact end of the solenoid. See my comment above and 65special's previous post. Thanks for the continued help! MP
Update: I never did find the culprit, so I cleaned house to hopefully prevent this from happening again: I had the starter rebuilt, installed a new solenoid and new starter relay, replaced the battery cable to the starter and replaced the S and R wires. Even though it was working OK I never fully trusted the carb starter switch, so I bypassed it w/a simple, spring loaded pushbutton switch, cleanly installed in place of the e-brake light. I relocated the e-brake light under the dash w/a little home made bracket. I've had a bunch of successful starts and a couple hours of run time w/no problems. Hopefully I'm in the clear, only time will tell. Thanks to all who contributed, I appreciate the help.
Glad you have it working to your satisfaction. A shame you had to abandon the carb switch. It's one of the things that makes your Buick truly unique, especially since that was the last year for it.
