Engine hard starting

J

Joe Scanlon

New member
My Model A engine is hard starting. I have replaced the coil, rotor, points, condensor, distributor cap, cleaned plugs and no improvement. It cranks for a good 30 seconds a couple of times before firing up on a warm day. Replaced the battery which had just celebrated its 3rd birthday but showed as weak after charging. It cranks over strongly. Checked the voltage at all ignition points per Les Andrews book. I open the GAV valve about 1/2 turn and choke it once while cranking. If I choke it again it'l backfire. I make sure that the popout ignition switch is out. After it finally starts it runs fine. What am I missing? Thank you all for your help!
 
The GAV on ours needs to be open at least one full turn. If not I have the same problem you have.

Choke once and than it starts.

Enjoy
 
Joe, is the backfire coming from the engine compartment or the tail pipe?

If the backfire is out the tail pipe you're likely too rich. If out the carb air intake, you're too lean. Check for air leaks at the manifolds.

I'm not sure what your experience level is. How many compressions are you holding the choke open for and what temp are you considering a warm day? As I recall, the Model A Owners Instruction Manual says to hold the choke until the engine fires and then immediately release the choke. The throttle position should be about 2-3 clicks down for a first start of the day???
 
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"It cranks for a good 30 seconds a couple of times before firing up on a warm day."

Is this after it has run or on a cold engine? How well does it start on a cold day?

Since you have replaced everything related to the ignition system, the only thing left is carburetor or compression. How is the compression? Have you checked it? How about trying a known good carburetor that you borrowed from a friend?

It could also be fuel flow from the tank. Test that by turning the fuel off and removing the plug under the carburetor. Place a bucket under the carburetor and turn on the fuel. Do this outdoors with a fire extinguisher handy.

One thing that happened with my car is a leaky float valve. The gasoline would flow into the intake manifold after I parked with a warm engine and flood the car with the vapor. It took lots of cranking to clear the flood, with a wide open throttle.

Rob Doe has some valid information. The Model A instruction book has some good information for starting, running, and maintenance of the Model A. The instruction book can be obtained from the usual suppliers. If the throttle is not opened 2 or more notches then the engine will not start easily. Another thing that may help, not in the instruction book, is moving down the ignition lever 2 notches from full retarded.
 
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You mentioned you have a pop out. Is it an original pop out switch? I had an issue with mine where it was making only intermittent contact when I turned it on. Some jiggling, some pushing in and popping out over and over and it might finally make good contact. With your situation, the vibrations from cranking might cause the ignitions switch to make contact. When it doesn't start up, leave the key alone, and take off the distributor cap. Open and close the points to see if you get a spark across the points. No spark could means that the ignition pop out switch isn't making contact (it could also mean that the pigtail wire in the distributor is shorting out).
 
Just reread this thread. Loose or contaminated wire and cable connections can steal the current from the Model A's ignition circuit. When taking a voltage reading at the customary wire connections with no current flowing, a low voltage reading is a good clue. A good voltage reading can be misleading. When current is flowing temperatures and resistance both rise and voltage drops. Ohm's law. Clean bright and tight on all connections, power side and ground side.

A low battery or a battery with weak but not shorted cell can fail to provide adequate voltage and thus current for running the starter and the primary ignition circuit at the same time. A low voltage and current in the primary ignition circuit will fail to fully saturate the coil. Weak secondary spark issues result. Add in a reversed polarity at the coil (or not) and the engine is hard to start or won't start.

The short version, try starting the engine with the hand crank.

One test is to voltage drop test the battery while cranking the engine. You can find proper, professional voltage drop tests in chapter 2 of Les Andrews blue book "Troubleshooting and diagnostics".

Les Andrew's red book repairs and replaces worn systems. The blue book teaches us how to keep the car moving down the road. The techniques described in the blue book are the same ones a Ford technician would use back in the day. IMHO, both books are required study for the novice Model A mechanic.

Twice in 23000 miles, the stacked connections at the starter switch caused issues on our car when loose or dirty.
 
Here is one way you can tell everything is set right,
After setting...cold start. Leave key off,open gav 1 turn, pull choke. Turn engine over two turns,push in choke. Turn key on and hit the starter....engine should start immediately and idle.
When Hot,engine will start immediately.
I have had A,s sit as long as a year, and they start like this.
 
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