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Jubilee died...beyond basic troubleshooting

3200 Views 5 Replies 5 Participants Last post by  BigH
It's rare I put up a post on any forum to seek help but I'm close to a loss on this one.
Senario: Never have problems with this Jubilee. Started it up and run it at low idle for about 10 mins before turning on the brushhog. Made it about 150ft and then it died as if I shut off the key. No sputter, pop, nothing. Acted like it lost spark so I pulled one of the plugs, grounded, and cranked engine. No spark. Checked another plug to confirm.
Spent a while looking and found the small copper strip from distributor post was grounding out on the case. Fixed that, checked with ohm tester to make sure it wasnt grounding out. I pulled the distributor to replace the points, condenser, and rotor at this time.
Put the distributor back in and checked for spark. All was good across all wires. Tried to set timing and I just can't seem to get it right. Turned over engine to 8 degrees, rotor pointing towards #1 on cap, adjusted slightly so points were just starting to open. Put everything back together and cranked engine.
Its back firing out the carb in that position. I rotated distributor over 180 degrees in small increments and can't find the right spot. I put marks on the distributor case and neck on block so I could line it up again and it seems close there but still no go.
Carb has been cleaned, getting fuel ok, and I compression is somewhat low but nothing below 85 psi but not above 90 either. Almost wondering if a valve is stuck open but found it odd to get that high of a compression reading with a stuck open valve.

Sorry for the long post but wanted to include all the details. Thanks for any help or insight.
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Sure you are on the compression stroke of #1 cylinder?..

I use my thumb over the plug hole wile cranking it in bursts to determone when its coming up to TDC on the compression stroke...then the distributor can be put in ,in the proper position..

You can set the timing with a test lamp by leaving it at TDC and hooking the lamp to the negative coil wire ,the points side,and to ground--slowly turn the distributor until the lamp just comes on,then tighten it there--that will be close enough to get it to start and then it can be timed with a timing light (or by ear!) after its warmed up..

If it still fails to run after doing that and it has spark (if its backfiring out of the carb I'd say yes!),then maybe the plug wires aren't in the right firing order--or maybe the timing gears have let the valve timing jump..

I dont know if these tractors used a fiber composition on the cam gear or not,many inline car and truck engines do and it can fail after a long time..also if the distributor uses a roll pin to hold the drive gear on it,check to see that hasn't been sheared and let the gear slip..
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I checked the valves by removing the side cover and all looked good. Figured if it was backfiring out the carb I must be 180 degrees off so I rotated distributor shaft 180 degrees. Basically rotor was pointed more towards #4 fire. Fired right up. Must not had it at TDC. Thanks
Some engines are designed to be timed off of the number 4 cylinder it's best to verify with a quality service manual or an old timer who has been there and done that

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Yeah, you gotta remember the timing marks come up twice per one turn ot the rotor so it is very easy to be 180 degrees out if you pull and replace the dizzy.
Once you had spark across all 4 wires, did you try to start it? Or did you dive right into the timing?

I recently fought a similar battle with my jubilee. What began last fall as bad points there were not opening to the right gap, progressed to a bad coil this spring. In the process of trying to fix that, I caused a new problem by grounding out the nut at the distributor. This was a maddening process to say the least.

If you dove right into the timing, then I wonder if you fixed your original problem, only to create a new problem to deal with. I suspected timing in my case too, but abandoned any efforts to adjust the timing for several reasons. First, my tractor was running, then died suddenly. How could that be timing? Either the timing is right or it isn't. It doesn't go from right to wrong all of a sudden. On top of that, the marks on the flywheel and the position of the rotor didn't make any sense. When the rotor was pointing at cyl #1, I couldn't even see the timing marks. They only appeared when the rotor turned 180 degrees. How could my tractor run if the timing was that far off?

I know that my jubilee had an engine rebuilt at some point in its past. I blamed the timing mark problem on the possibility that the flywheel was not reinstalled in the correct position. Having never seen this tractor ripped open, I have no idea whether that is even plausible. But I decided to put my faith in whoever timed the thing before me, and didn't adjust the timing at all.

I am glad I didn't. Once I really solved all of my ignition problems, the jubilee started right up. If you dove right into timing, you might want to try returning the timing to where it was (or as close as you can remember).
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