Farmall 340 - No Spark

John Ratu · Nov 12, 2009

My 340 utility has no spark at the plugs. Have installed new points, condenser, rotor and coil. Have 6 volts at battery side of coil. Drops to 4 volts while cranking. Just rebuilt all the plug wires and have continunity from distributor cap to plugs.

Leon Torkelson · Nov 12, 2009

Try putting your old condenser back in. It wouldn t be the first time that a new forgin made condenser didn t work.

old · Nov 12, 2009

Open your points by hand with the switch on. You should see and hear the spark there if you do not then you either installed the point wrong, easy to do by the way or you may have a bad new condenser also very common now days

Brownie 450 · Nov 13, 2009

How about spark from the coil to the dist cap? Pull the wire out of the center of the cap, & hold it 1/8 inch from a ground & see if spark jumps the gap. Did you replace the coil-dist wire also?

El Toro · Nov 13, 2009

Check your battery's electrolyte with a hydrometer and see what each cell reading is, should be around 1.250 or better. You may not have enough battery voltage. Hal

ScottyHOMeY · Nov 13, 2009

If your voltage is dropping like that, I'd suspect a battery issue. Are your new/rebuilt plug wires solid core/i.e., not resistor wires?

Still there's the crazy stuff. Is there spark to the plugs, at all? You might be way out of tiome. There's been a couple of cases lately of being 180 out. If there's spark from the coil but none anywhere to the plugs, a look around to see if your rotor button might be sitting over on the bench could be worthwhile. If you won't ask I won't tell how I happen to think of that one.

Mark · Nov 13, 2009

Hehehe......based on the fiasco I just went through, I think checking that 180 out is the first thing I'd do!

Janicholson · Nov 13, 2009

If it ran before you did the tuneup, it may need the little insulator at the distributor connection pass through reset. the little bolt can touch the housing.
With the ign on, remove the wire at the distributor. then brush it up against the terminal. if it sparks (low voltage spark) the coil is probably OK. Do as Old indicates to see if the points are working. JimN

El Toro · Nov 13, 2009

Even if the distributor is 180 out you can still have fire to the plugs, but it won't start. Hal

John T · Nov 13, 2009

That drop from 6 down to 4 volts worries me. If the battery and cables and grounds and starter motor and solenoid are allllllll good Id expect more like at least 4.5 to 5.5 maybe (depends on battery n starter and temperture etc) . Id have the battery load tested and then remove, clean n wire brush n reattach each n every battery n starter n ground cable and try her.

Also check the ignition switch (burned resistive contacts), try to by pass the switch by hot wiring the coil and see what the coil voltage does then????

Then use my Troubleshootign Procedure below where you place a test lamp or voltmeter on the TO DISTRIBUTOR side of the coil and look for the lamp to flash on (poinst open) then dead off (points closed)

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=5745

John T
John Ts Ignition Troubleshooting

ScottyHOMeY · Nov 13, 2009

Only brought it up becasue in both the cases I mentioned the posters were reporting no spark at the plugs. Turned out (eerily so, for two cases so close together in time) that there was spark to the plugs, just not where they were looking for it.

Just trying to cover bases.

Farmall 340 - No Spark

John Ratu

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Leon Torkelson

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old

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Brownie 450

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El Toro

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ScottyHOMeY

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Mark

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Janicholson

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El Toro

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John T

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ScottyHOMeY

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