JD 300 gas 1970 year model no longer runs

cstokes · Aug 2, 2015

I am looking for help troubleshooting the ignition system on my JD 300 gas. I believe it has been altered from its original stock wiring and the 2,2 ohm resistor wire removed. I have had it for about 10 years. about a year ago or a little over it started running rough and got hard to start. I started with a tune up kit consisting of cap rotor points and plugs. it got worse if anything. since then I have replaced the coil and the carburetor. it doesn't run at all now. I have had 2 mechanics look at it, with no better results than myself. any help will be appreciated.

fixerupper · Aug 3, 2015

How is the compression? A couple years ago a neighbor brought over a tractor with those symptoms and it turned out the compression was so low it couldn't draw air through the carb fast enough to get fuel.

cstokes · Aug 3, 2015

(reply to post at 04:34:13 08/03/15)

I checked compression 120 in all three cylinders
Thanks

CPeter · Aug 3, 2015

The one thing I did not see mentioned was the condenser. That would have been the first thing that I would have changed along with the points.

Do you have voltage to the points? If yes and you have replaced the coil, cap, wires and rotor, then the only thing left is the condenser. The new condensers are crap. I have to test all of the new ones I install to see if they are anywhere near in spec.

Another question. Does the distributor shaft turn? You might have sheared off the pin the holds the gear onto the shaft. That would have thrown the timing way off and made it run bad and not the shaft is not turning at all.

CPeter

PopinJohn · Aug 3, 2015

Have you tried starting with the air cleaner disconnected?
If it has a bird nest in it; will cause those symptoms.
Mike

nlastovi · Aug 3, 2015

(quoted from post at 19:02:59 08/02/15) I am looking for help troubleshooting the ignition system on my JD 300 gas. I believe it has been altered from its original stock wiring and the 2,2 ohm resistor wire removed. I have had it for about 10 years. about a year ago or a little over it started running rough and got hard to start. I started with a tune up kit consisting of cap rotor points and plugs. it got worse if anything. since then I have replaced the coil and the carburetor. it doesn't run at all now. I have had 2 mechanics look at it, with no better results than myself. any help will be appreciated.

I'd suggest beginning with basic troubleshooting... Does it have spark? Is the timing correct? Does it have good compression?

If all of those are proven good, then move along to the carb. Are the plugs, after trying to start it, wet or dry? Dry would lean you towards a fuel supply sort of problem and wet might tend to suggest too much fuel.

cstokes · Aug 4, 2015

(quoted from post at 09:40:18 08/03/15) The one thing I did not see mentioned was the condenser. That would have been the first thing that I would have changed along with the points.

Do you have voltage to the points? If yes and you have replaced the coil, cap, wires and rotor, then the only thing left is the condenser. The new condensers are crap. I have to test all of the new ones I install to see if they are anywhere near in spec.

Another question. Does the distributor shaft turn? You might have sheared off the pin the holds the gear onto the shaft. That would have thrown the timing way off and made it run bad and not the shaft is not turning at all.

CPeter

I have had the distributor rebuilt and pertronix pointless ignition kit installed. it tests fine on the bench. i am going to go wire by wire from the ignition switch to the starter and coil. some of that is not original. I am not sure that it still has the 2.2 ohm resistor wire in place.

JD 300 gas 1970 year model no longer runs

cstokes

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fixerupper

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CPeter

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