starting farmal super h

trpaul1

Member
my super h is hard starting. at overhaul I converted it to12 volt. Now it is difficult to start. It cranks fast, but only starts as cranking stops. I can only guess, it is timing, wiring or fuel. Sometimes it starts and runs ok. Ideas? Thx
 
by chance, did you install a starter solenoid? it could be the coil is not getting enough juice to fire when the starter is engaged. make a jumper
wire with a couple alligator clips, the hook one end to the hot side of the ignition coil and the other to the hot side of the battery. then try and
start it. CAUTION.... the ignition is hot wired now and the engine will NOT shut off until you remove the jumper. if the tractor starts right up, you
found the problem. if you have a solenoid with two small terminals, the second little terminal supplies direct 12 volts when the solenoid is
engaged. run a wire from that post to the hot side of the coilfor a second power supply during start up.if you hace a ballast resistor before the
coil, hook this wire directly to the coil, bypassing the resistoor during starting.
 
A starter going bad will do that due to pulling to many amps so robs the ignition of power so no start. Or you have it wired in such a way that when the starter is spinning the switch does not have power to the coil
 
?at overhaul I converted it to12 volt. Now it is difficult to start.?

Sounds like too much resistance in the coil circuit. With 12 volt system resistance from + to ? on the coil plus the value of any added resistor should equal about 3 ohms. Significantly more resistance gives the symptom you describe.

Did you use a conversion kit to go from 6 to 12? If so, there are 2 common problems with installation of the kits.

1. Replacing original 6 volt coil with a ?12 volt no resistor required coil? and then installing the resistor that came with the kit. If so, remove the resistor.

2. Using the original 6 volt coil with the kit resistor. But the kit came with a resistor of too high a value. If so, replace resistor with one that is near 1 1/2 ohms.

If it has a resistor, jumper across it and if engine starts like it should you have isolated the problem.

The resistance of a 6 volt or ?12 volt external resistor required? coil should be 1 1/2 ohms and the added resistor should be close to 1 1/2 ohms. I know of an 8N and Jubilee Ford that had same symptom of not starting until start button released. Both of those had a conversion kit resistor of 5 to 6 ohms resistance. On one the coil and resistor was replaced with a direct "12 volt no resistor required" coil. On the other the resistor was replaced with one that measured 1 1/2 ohms. Both then started like they should.
 
(quoted from post at 08:48:10 04/18/18) A starter going bad will do that due to pulling to many amps so robs the ignition of power so no start. Or you have it wired in such a way that when the starter is spinning the switch does not have power to the coil

direct hot wiring the battery to the coil worked. Is there any way to wired this for a permanent fix? thx for all responses.
 
You were right on. DiThrect wiring the battery to the coil was successful. Thx. Is there a fix to make this permanent?
 
Have you checked the voltage at the coil while cranking with an analog meter?

If there is an ignition resistor, and it drops below about 4 volts, or if no resistor it drops below 8 volts or so, there is high resistance somewhere between the battery, or ignition switch, and the coil. It is difficult to get a good reading, as the voltage will fluctuate as the engine turns through, just try to get an average. It could possibly have a bad connection or bad switch. If there is a resistor, try connecting the jumper wire ahead of the resistor, (pull the coil wire to prevent starting) do some voltage comparisons to locate the voltage drop. If the switch and wiring are good, you should get close to the same voltage to the coil (or ahead of the resistor) as across the battery while cranking.

Do you know what coil it has? If you have an ohm meter, check across the primary terminals of the coil (out of circuit).

A 6v coil will have about 1.5 ohms.

A 12v coil that needs a resistor will have about 1.5 ohms.

A 12v coil that does not need a resistor will have about 3 ohms.

End result, there should be about 3 ohms, including the resistor if equipped, across the coil circuit. If the wrong coil, as in a 12v with 3 ohms, is used with a resistor, the end result will be a weak spark, especially when cranking.

There is a way to connect a resistor bypass, but it is only necessary with large, high compression engines. When you get the problem solved, your application will start easily without a bypass.

Other possibilities could be a weak coil, bad points or condenser, loss of spark between the coil and the plugs, as in bad wires, rotor or cap, even bad plugs can do strange things.
 

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