john deere 420c Running on 1 cylinder.... Help!!

[E.Huffman]

So i have a newer (1958 or newer) 420c that i am having issues with running on one cylinder. the plugs,wires and cap/points are all good. however when we rotate the whole distributer 180 degrees it switches from the front to the back cylinder still running on one cylinder and vice versa when switched back. Any ideas on what to do we are kinda stumped! Thanks in advanced

[Jim B]

This sounds familiar. Did you just replace the distributor cap? If so click this link: viewtopic.php?f=1&t=12390&p=69224#p69224 and read the thread. It's a starting point.

[E.Huffman]

I do believe this might be my issues! I have a 12 volt system with a "6 volt" cap!

[Jim B]

Distributor caps do not care about voltage. You need a cap for a Dubuque built 2 cylinder engine which would have had a 6 volt electrical system. When you look at the cap there should be a spark plug wire terminal both sides of one clip that hole the cap on. If the plug wires are between the clips it is the wrong cap.

[E.Huffman]

Ok well if it doesent care about voltage then I am stumped because thats what i HAVE.............

[Jim B]

A distributor cap has no primary wires going to it. The cap receives the secondary voltage (20,000 plus volts) from the coil wire in the center and the rotor button directs that voltage to the plug wire terminals. The cap does not see either 6 or 12 volts. If the spark plug terminals are on each side of one of the cap clips it is the proper cap and not the problem. If the plug terminals are between the two cap clips it is the wrong cap. Where are the plug terminals on your distributor cap in relation to the clips?

[E.Huffman]

so I have the one that has terminals on each side of 1 clip like the right one you were describing. So we even took the whole distributer assembly off our john deere 40 wheel tractor (it has the same dist) and still only one cylinder. It has become quit a frustrating problem!

[B Town]

Can we have some background on the machine. Like when was the last time it ran correctly, has the motor ever been apart etc.
Best regards, Bruce

[E.Huffman]

Honestly I just bought it 2 days ago has'nt run right since I got it, how ever we turned the oil pump timeing 180 degrees and works beautiful! Thanks alot!

[B Town]

I wondered. Someone has been in there before you and been causing problems. Glad you found it.

[Jim B]

E.Huffman,

Glad you found the cause. I went for the cap as I have been given the wrong cap before. Some parts books list the Waterloo cap as a 12 volt cap and the Dubuque cap as 6 volt. The parts person asks 6 or 12 volt and if a conversion to 12 volts was done, the answer is 12 volts. Reality is the cap doesn't change any more than the rotor, points, or condenser do with a conversion. Just curious, if the way it was running, and the previous owner couldn't fix it, was part of the reason it was available? Did you know if he had replaced the oil pump or done an overhaul, and then had this problem?
Did you check out the 430C Operator's manual? Is that the info you needed?

Good call Bruce, on asking about a the history. I was only thinking of a simple cause, like a parts guy handed out the wrong cap with tune up parts.

Jim

[E.Huffman]

So It looked like it had head work done within the last 5 years but I had no idea what, the man that owned it had a brain injury and his wife was just trying to get rid of it. So when we were messing with the spark plugs we happened to look into the block and judging by the way the side wall looks in the one cylinder it has had a snapped rod in the past..... yes it has a nice big gouge in it ....... Also we noticed it has .45 overbored pistons in it. Just to be clear it does not have a snapped rod currently. Obviously I knew none of this until i got in the shop to work with it.... I think it will be ok It is definitly a mosquito killer!!!!

[E.Huffman]

E.Huffman,

Glad you found the cause. I went for the cap as I have been given the wrong cap before. Some parts books list the Waterloo cap as a 12 volt cap and the Dubuque cap as 6 volt. The parts person asks 6 or 12 volt and if a conversion to 12 volts was done, the answer is 12 volts. Reality is the cap doesn't change any more than the rotor, points, or condenser do with a conversion. Just curious, if the way it was running, and the previous owner couldn't fix it, was part of the reason it was available? Did you know if he had replaced the oil pump or done an overhaul, and then had this problem?
Did you check out the 430C Operator's manual? Is that the info you needed?

Good call Bruce, on asking about a the history. I was only thinking of a simple cause, like a parts guy handed out the wrong cap with tune up parts.

Jim

Thanks a lot for that info as I did not know that there were specific caps for the dubque tractors!!!!

[dtoots1]

definitely is the wrong cap!!! you can order the correct one directly from Lavoy, owner of tis site and basically all parts needed...

i too had run into same problem, get correct cap and problem solved.

[E.Huffman]

definitely is the wrong cap!!! you can order the correct one directly from Lavoy, owner of tis site and basically all parts needed...

i too had run into same problem, get correct cap and problem solved.

The cap I have is the right cap. I have it running great on the cap it has.