When I depress the starter foot pedal the starter turns several revolutions but then stops. It does not continue to turn over the motor. I can immediately depress the foot pedal and it once again turns several revolutions but then stops. The battery is fully charged. I have only owned this auto for several months and prior to this the starter would continue to turnover the motor until it started. Could this problem be a failing "starter motor switch" which is mounted on the starter motor? This is a 6 volt system with a Delco-Remy starter motor.

Possible causes,
Defective battery, starter switch, battery cables , poor cable connections, or starter,

agree with gene... when you kick the starter over it pulls a TON of AMPS to spin the starter !! what you are describing really sounds like a battery on its last leg ? been there recently. does it spin it at full speed like normal or just slowly ?

1-would check cables, mainly ground (make sure it is robust and connects to clean bare metal on the frame) and that the power that goes from battery direct to the starter is a robust cable and no corrosion on either end. i use 00 cables for power and ground on my 1929.
->you can check if it is the ground cable by using a set of jumper cables and connecting the ground from battery negative to one of the bolts holding the starter to the housing, or clean metal close by on the trans, engine, housing.

2-battery (how old is it ? typical life is 3-5 years (can last longer +2 years if battery spends life on a maintainer when not in use) can test this as well if you have a spare 6v around, if not you can use a 12v in parallel with the 6v, but do NOT leave it connected !! i put the 12v on the ground near the battery, run jumper cables from 12v to 6v in parallel (+ to + & - to -), i do NOT connect the ground until i am ready to try and start the car. do this all by hand, i make sure all electronics are OFF (lights, etc) then turn on key, and push the starter pedal with my left hand as i touch the 12v negative to the 6v negative. see if starter picks up and spins harder and faster. 12v will NOT hurt the starter only electronics in the car (lights, etc) only do it for about 5-6 seconds then pull away the 12v negative and release the pedal.

the starter switch is just a simple contact switch. can look it over and see if it is gunked up, but they typically last forever. remove power and then the 2 screws and they come right off and you can see the simplicity. if bad they are readily available on the market NOS, NORS, etc...

you can also pull the starter and put in on your bench, i put mine in my vise and used jumper cables to connect to my 6vbattery to make sure it would spin up. if it is bad complete rebuild kits rare readily available. have rebuilt 2 of them to date. complete rebuild kit has armature, brushes, bearing/ bushing, and bendix.

I appreciate the suggestions provided, and please note the following:
1. The battery is only 9 months old and I have had it checked out and it is good. It is a 640 CCA with 130 RC. and I keep it on a battery retainer.
2. There is no corrosion on the ends and all fittings are secure and the cables are heavy duty for a 6 volt battery and I did remove and inspect the starter switch and it makes good contact when the starter pedal is depressed.
Today the outside temperature was in the mid 60's and the starter did continue to turn but at a slow rate, and as I mentioned earlier I have only had this car since September and I realized this problem only began when the temperature was much colder (under 50 degrees).
Would a higher CCA battery solve my problem? Especially in colder weather? What should be the minimum CCA for this starter/engine?
Thanks for the assistance

thanks for the update...

battery is typical CCA for a 6v battery. i use an optima 6v Red Top (800CCA 1000CA), totally different world.

what size/gauge are you cables ? did you try the jumper cable trick noted above ?

did you try to parallel the battery to see what that did ?

did you pull the starter and bench test it ? ( 2bolts +1 nut for wire removal ) 5 minutes to remove 5 minutes to install.

With that information I would overhaul the starter if it were mne.

While the cables might be labeled “heavy duty” what counts is the actual gauge

I used 2/0 on my ‘37 and never had any starting problems - until the battery died after 7 years!

Where does your ground cable connect?

I have also been using an 6V Optima Red top for several years. Starter spins over like a 12V.

The last Optima lasted 9 years.

Hello Reedster101,
All these suggestions concerning your starting system are right-on. As you have stated, your problem seems to have appeared as the temperature has become colder. Expansion and contraction of all components should be considered. All electrical connections need to be clean and tight. Starter ground also needs inspection. Paint and contaminates/dirt/grime needs removal for good electrical connection. Try grounding the starter directly to negative at the battery. If no improvement, suspect failed battery and/or starter. Cold engine and transmission oils contribute to the need for a healthy starting system.

Probably not a good suggestion, but I would try to turn the engine by hand to see if it seems unusually tight. Was it rebuilt recently?

I've had the same situation as the poster describes. I've optimized all components, cables, re-built starter, etc, AND have 2 Optima batteries in parallel.

She almost always stops and grunts after a few revolutions, but will recover if I give it a few seconds "rest".

I chalk it up to a tightly re-built engine that still has under a 1000 miles on it, not full broken in.

So I live with it. Hand cranking is also very hard.

After additional review of the positive battery cable I now realize the overall OD of the cable is approximately 1/2 inch which means the cable is only GAUGE 2. Not a heavy duty cable. I am ordering a custom 4/0 (0000) cable and this will hopefully solve my problem.
I thank everyone for their suggestions which has been very helpful. I've never had a 6v system prior to this and didn't realize the importance of the cable size.
Regards

good to hear, how about the ground ? it is most important of them all.

6v system typically requires twice the diameter wire to get the same umph vs 12v

Respectfully,

Actually, the positive and negative sides are "equally" important.
Granted that the negative side may be more prone developing resistance problems.
Electricity doesn't however care where the resistance is, so cleanliness on your positive cable is equally as important.

yes they are equally important, studied electronics :)

was a generalization with these cars people always over look the ground. they go big on the positive cable and overlook per say the ground/negative. i ran same gauge on both plus ran extra ground to ensure a solid frame ground :)

👍 🙂

I would be cautious about going to such a large cable. Make sure they will bend tight enough to fit your application.

The 2/0 cables on my car were pretty tricky to route and get connected. I doubt if I could have used anything stiffer.

If you are changing the battery cables check out "BatteryCablesUSA". I purchased mine from them for my 31. I also have the ground attached to the bell housing. You can purchase the gage you want, different lengths with specific ends. Good Luck.

I think most heavy duty truck dealers or repair shops can make cables of 2/0 size . BY heavy duty I am referring to class 8 trucks such as Volvo-Mack-Peterbilt-IH ETC.