Model A turns over, but won't start

J

jjspock

Junior Member
I am trying to sell a 1931 Model A coupe for a friend. It's sitting in my garage and started easily when we put it there 2 months ago. I've been starting it regularly and last time I did, I forgot to shut off the key. Now it turns over but as soon as it fires up, it stops firing, the starter disengages and I can hear it whirling. I put in a new bendix and a new coil but no change. It has spark and gas. Can you help? I'm flummoxed.
 
I’m just guessing, but if the key was on and the points happened to be closed, you may have damage to the points, the coil, or the notorious condenser. I’d start by switching in components that are known to be good before anything else.
 
Check the resistance of the primary windings in the coil. If the car is still 6 v, it should read about 1.5 ohms. If that is OK, it is probably the points have been fried as David in San Antonio says. Condenser is the next in line IMO.
If they all check out OK, follow the ignition system wiring from the battery end to the points checking for voltage as you go.
 
Synchro, He posted that he put in a new coil. But it could be bad out of the box so checking the resistance is still a good idea. It if fires up but then quits it is either the points or more likely the condensor.
 
Hello, as mentioned condenser is a known trouble spot , first thing I look at if it running erratically or not running at all , also check points , then wire in distributor that connects the plates .
 
OP states IT HAS GAS AND SPARK. Where and how did you check for spark and gas? Are you saying that it fires and when it fires the starter bendix disengages?
 
About condensors: The condensor is an active component of the ignition system. If it is bad there can still be a spark when tested without the engine running but the points will immediately burn and the engine will stop running or run erratically. I know this from theory and from my personal experience on my 29 pickup.
 
Thanks David in San Antonio. I did replace the coil and will replace the condenser next. I dread doing the points and they seem to be okay from a visual inspection. The amp meter doesn't wiggle when I'm turning it over and, according to Paul Shinn videos, that means voltage isn't there. So it's got to be somewhen upstream.
 
So to me it sounds like you’re not that familiar with A’s ? Clean and gap the points, start with the hand timing level up, the hand throttle down a coupe of clicks for a fast idle, GAV open 1/2-3/4 , turn the key on, pull the choke out and hold it for 2-3 times while the engine is turning over, release the choke or push it back down, the engine should be run at a fast idle . Are the spark plugs wet from too much gas ? If the starter continues to spin after releasing the starter switch ( not turning the engine) the switch it sticking and should be addressed . Good luck on the sale of the A
 
I checked for spark at the rotor arm just upstream of the points and I can hear the spark jumping the gap. When cranking, it seems to fire once and the bendix disengages and whirls. I haven't checked the resistance on the new coil but will when I replace the condenser. You guys are great.
 
The easy way to clean the points is with some wet and dry sanding paper. I use 400 grit but a courser grit will also work. Fold a little piece in half and turn the engine so the points are closed. Open the point with your finger and insert the sand paper. Run it back and forth a few times. Now clean out the grit with a piece of cardboard and then snap the points closed a few times by pulling them out and letting go.

If the ammeter is not wiggling then the points are dirty and not conducting. Or the ammeter wiring has not been updated to show the wiggle. Measure the voltage at the movable point with them closed. The voltage should be close to zero. Also measure the voltage at the movable point with the points open. The voltage in this case should be equal to your battery voltage. Just looking at the points will not provide you with enough information.

Follow the starting procedure that the Big Hammer outlined above in Post #9.
 
Last edited:
X2 what nkaminar said.


If the ammeter is not wiggling then the points are dirty and not conducting. Or the ammeter wiring has not been updated to show the wiggle.
 
I bet I know what it is. Hard gas in one of the jets on the carb. You can unbolt the bottom half (if your are fairly skilled), or drop the barb off. Take a little wire, and run it through the jets. This wire needs to be small! Put it back together and problem solved.

Doubtfull the float is sticking.
 
To test, get an assitant and as it dies a very short shot of WD-40 to catch it. That will verify that it is fuel related, and not spark. Back it out of the garage, as accident sometimnes happen. Remember, you don't need to drive the thing, just diagnose, so don't get carried away.
 
I'm not familiar with Model A's but I did watch a bunch of videos and have started it several times, just like you described. The bendix disengages and the starter whirls before the engine catches. Haven't checked spark plugs yet either. The condenser has zero resistance so that, hopefully, is it. I ordered a new condenser that won't arrive for a couple of weeks and I didn't want to proceed with the points until I swapped that out. I had my son spray engine starter fluid up the carburetor air intake and that did absolutely nothing so pretty sure it's electrical. But I have a gentleman coming this morning to look at her. He's not worried about it not starting as he's owned four Model A's in the past. He's bringing a trailer and cash so I'll probably be saying goodbye to the old girl today. She was fun working on and if I had a garage, I'd buy her myself. You guys are great!
 
Check your Ground! Just to be sure, if for no other reason. I had a similar type problem with my '32 for a while. Hit n miss start with key, then got worse!! Crank good, no start! But when I let key go to OFF... a momentary firing/attempt to start. I finally... traced it down to loose ground. Cleaned all that up... batt to solenoid. And added an add'l engine to frame grounding strap.


Once I did that, never had any starting problems again.


Electricity can act funny at times, yet be no joking matter! ;)
 
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