Failure to start

[DennisH]

I work at a county fair ground and we have a Ford 641 tractor that runs well but it won't start with the starter button. With the ignition switch off I get power that should start the engine but the starter button gets no juice so the engine won't turn over. With the switch on the starter turns the engine over but there is no spark to start the engine. It seems that a wire is crossed somewhere but according to the wiring schematic the tractor is wired correctly. The tractor starts quickly when towed. Does someone have any suggestions to where to look or what be wrong.

 

[old]

Starter could going bad and pulling to many amps so no power for spark. My self I would first try hot wiring it and see if it starts then. If it does then you have bad wire or connection

 

[rew1953]

Sounds like the all too common ground problem that causes many non-starts. My NAA has the same problem, but periodic. I got some paint inside the starter button housing which is preventing good grounding. Have to rotate button by finger a few times to get it going. A bad ground is hard to chase down. You can hook up a test lead from the hot wire at the push button and touch it to a ground to see if the solenoid will fire.

 

[steve_in_mo]

Bad ground or maybe bad ignition switch.

 

[old]

I just thought of this. Last week I got phone from some one who us to be on this site with a problem like your having. He had a bad connection at the wire at the start button. He cleaned that tab it hooks to up and it starting working just fine. By the way if you take that wire off the starter button and ground it to a known good ground with the ignition turn on it should spin the engine over

 

[DennisH]

Thanks, I'll look into that also.

 

[DennisH]

Thanks, I'll look into that suggestion.

 

[DennisH]

That's something to check.

 

[DennisH]

(reply to post at 14:31:49 06/01/20)

Thanks.

 

[showcrop]

The starter button is not a starter button. It is a momentary ground for the coil of the starter solenoid. There is not supposed to be "juice" to it. The starter solenoid has not been recently replaced has it?

 

[showcrop]

The starter button is not a starter button. It is a momentary ground for the coil of the starter solenoid. There is not supposed to be "juice" to it. The starter solenoid has not been recently replaced has it?

 

[Steve@Advance]

Do you have a volt meter, preferably an analog, or even a test light?

Connect the meter/light from the ignition side of the coil to ground.

If it has a neutral start switch, put the transmission in gear to disable the starter. If no neutral switch, remove one of the small wires from the solenoid.

Turn the ignition switch on. You should have power at the coil.

Turn the switch to start and watch the meter/light. It should have power when in the start position. Try it several times, the voltage should be steady and never drop.

If that tests good, the wiring and switch are good.

Reconnect the starter. Remove the coil wire so it wont start. Give it a crank and watch the voltage. It will drop somewhat but should remain reasonably high. If there is a resistor, try testing on the ignition switch side of the resistor. With a volt meter the reading needs to stay above 9 volts.

If it is dropping too low, there is not enough power left to make a spark.

Could be weak battery, bad connection, too small battery cables, or a dragging starter.

Feel the cables and connections for hot spots, all the way to the starter.

Have the battery load tested. How's the charging system?

And it could be just in need of a good tune up, plugs, wires, points, anything else about the ignition system that appears to need attention. A good ignition system will give a blue hot 1/4" spark at the plug end of each plug wire to ground when cranking.

 

[DennisH]

Yes the solenoid was just replaced and you are right, the starter button is a momentary ground. The wire looked weird but upon thinking about it you're right

 

[showcrop]

(quoted from post at 16:02:35 06/01/20) Yes the solenoid was just replaced and you are right, the starter button is a momentary ground. The wire looked weird but upon thinking about it you're right

The wrong solenoid was installed. You have to get one that grounds through a terminal instead of through the bracket of the solenoid.

 

[DennisH]

We have a solenoid that grounds through the terminal on it but I will check the connections for clean.

 

[rew1953]

(quoted from post at 15:32:58 06/01/20)
The starter button is not a starter button. It is a momentary ground for the coil of the starter solenoid. There is not supposed to be "juice" to it. The starter solenoid has not been recently replaced has it?

My NAA owners manual and shop manual refer to the "switch" as a starter button. The parts list from this site and four other parts houses I use all refer to it as a starter button. My NAA has power to the starter button full time. You can rotate the motor with the ignition switch in the off position. It is a factory wire to the starter button.

 

[DennisH]

The tractor has an on/off key switch next to the steering wheel and it controls the starter button on the transmission just in front of the shift lever. If the key switch is turned off the starter button does not work but turned on the starter button does.