Are you sure you have a No,Weak or Good spark?And if your starter with normal speed?

[Fernando Mendes]

They are a very difficult symtoms to see.

Let's see the following sequence.
ENGINE FAILS TO START-MISFIRES-OR RUNS UNEVENLY

 

APPLY STARTER...........1.STARTER CRANKS ENGINE WITH NORMAL SPEED...1a.ENGINE DOES NOT START...1b.ENGINE MISFIRES OR RUNS UNEVENLY

 

1.a.1.DISCONNECT SPARK PLUG CABLE AND HOLD 1/8" FROM ENGINE WHILE STARTER CRANKS ENGINE(WHO HOLD?)...1.a.1.a.NO SPARK...1.a.1.b.WEAK SPARK...1.a.1.c.GOOD SPARK.

1.b.1.CONTINUOUS MISFIRING IN ONE OR MORE CYLINDERS...1.b.2.ERRATIC MISFIRING OR ENGINE RUNS UNEVENLY.

 

2.STARTER DOES NOT CRANK ENGINE OR TURNS IRREGULARLY.

2a.BATTERY DISCHARGED,POOR BATTERY CONNECTIONS,STARTING MOTOR DEFECTIVE.

[jeffsunzeri]

Actually, all of those symptoms are fairly easy to see, diagnose, and fix with the appropriate tools.

 

The best tool for diagnosis of all the items you mention is an old Sun (or equivalent) diagnostic station, with a complete scope and meters. The companion tool is a distributor machine which will diagnose all sorts of issues related to the distributor. Champion also made a good ignition diagnosis scope suitable for the small shop, and it's available on eBay from time to time, with the instruction manual.

 

Of course the best tools are no good unless the technician knows how to use them. Sadly, I don't think there are many mechanics around with that knowledge, but an astute person with a little time can teach him or herself using the old manuals that came with the systems.

[bach4660]

They are a very difficult symtoms to see.

Let's see the following sequence.

ENGINE FAILS TO START-MISFIRES-OR RUNS UNEVENLY

 

APPLY STARTER...........1.STARTER CRANKS ENGINE WITH NORMAL SPEED...1a.ENGINE DOES NOT START...1b.ENGINE MISFIRES OR RUNS UNEVENLY

 

1.a.1.DISCONNECT SPARK PLUG CABLE AND HOLD 1/8" FROM ENGINE WHILE STARTER CRANKS ENGINE(WHO HOLD?)...1.a.1.a.NO SPARK...1.a.1.b.WEAK SPARK...1.a.1.c.GOOD SPARK.

1.b.1.CONTINUOUS MISFIRING IN ONE OR MORE CYLINDERS...1.b.2.ERRATIC MISFIRING OR ENGINE RUNS UNEVENLY.

 

2.STARTER DOES NOT CRANK ENGINE OR TURNS IRREGULARLY.

2a.BATTERY DISCHARGED,POOR BATTERY CONNECTIONS,STARTING MOTOR DEFECTIVE.

Not sure if reading this right, the top part is the question, and 1and2 are possible solutions?

 

Step one, is to make sure the battery is fully charged and in good shape, if it is old/weak you will get a few good cranks and then nothing.

Two- when checking for spark, I never hold anything, I usually use a vise grip to hold the spark plug to the block ( I hate shocks, even hate the thought of a shock)

 

other than the usual, checking the condition of the plugs, gap etc. I found with my PH I had a bad ground where the wire came through the casing of the distributor (on a post). I changed, plugs, condenser, coil as I had intermittment and weak spark. Finally I saw that the bakelite insulator had broken off, I used the plastic from a disposal pen to make a small insulated tube, stuck into into the distrubutor and started. Still running today

[Fernando Mendes]

Yes,1 and 2 are possible solutions.You have a good idea to put a vise grip to hold the spark plug to the block.

[Fernando Mendes]

If you have NO spark:

a)Ammeter shows no discharge-zero reading....primary circuit is interrupted

*breaker points are excessively burned or pitted

*breaker points  in distributor not closing

*loose connections from starter to ignition switch

*primary wire from ignition switch to coil or from coil to distributor may be broken or connections loosened

*ignition coil primary windings may be open

*ignition switch is defective.

b)Normal ammeter reading...needle oscilates between TWO and FIVE amperes discharge while starter is cranking engine...primary circuit is complete.(check secondary circuit)

*High tension wire from coil to distributor may be broken or grounded

*Defective ignition coil or condenser

*Defective distributor rotor or distributor cap

*High tension wires may be wet.

c)Ammeter indicates abnormal discharge-more than TWO to FOUR amperes...a short exists between the ammeter and the ignition coil or in primary winding in ignition coil or in distributor as follows

*Distributor points may not be opening

*Condenser may be "shorted"

*Primary winding in ignition coil may be "shorted"

*Breaker point arm in distributor may be grounded

*Wire from ammeter to ignition switch or from ignition switch to ignition coil may be "shorted" or grounded.