Here’s the latest update. This afternoon, I tried starting the engine dead cold. It started, but not after I had flooded it. With the new carb kit and the new fuel pump having far more pumping ability than the original pump, I will need to learn how to start it again, like a new-to-me outfit again. Not sure if I will leave this new fuel pump in there, as the old one was probably fine, not to mention it had a lower pump output which seemed a good match to the carburetor.
Anyway, after the flooding episode, it started. First, I ran it in the garage at low, then high idle for about five minutes. At both rpm ranges, the engine mostly ran smoothly, but with single spark misses every 2 to 3 seconds. Something not right to cause that, but wasn’t sure what it may be. But, as I will describe next, it is probably related to what happened next, when I pulled out of the garage, engaged the mower deck, and began to mow grass. After mowing about 40 feet, the engine stopped dead. I cranked it over for about two seconds and it re-started.
At this point, the deck is disengaged, so all that I am trying to do is drive it back into the garage. So, after the restart, I was able to touch the foot hydro pedal and move it about five feet. Then, the engine stopped dead again. Restarted it once more, and moved it another five feet before the engine stopped again. But, now, it won’t restart at all.
So….to get it back into the garage, I cranked the starter and engaged the hydro pedal to move it ever so slowly until it was back into the garage in a dark space. No way will one person push this thing one inch while the hydro is still holding pressure, and the bypass valve is located in a nearly inaccessible location beneath the pan which supports the seat, only accessible by removing the pan which covers the entire differential, axles, and hydrostatic pump. Cranking the starter and inching it is by far the simplest way to get it back into the. garage, even though I prefer to not resort to that method.
Once in the gargage, I opened up the engine hood/bonnet to do two things: First, check for spark. Using the newly acquired Oregon spark tester, I was able to see zero spark in the dark garage. Not one arc. Nada. Obviously, the engine had been running before, so the coil was generating spark for that to take place. But, once hot, the coil stopped putting out spark. Second thing I did was to check compression while hot. I mentioned up thread that the cold compression was 108 psi. Taking a new test while hot, the compression was a consistent 105 psi, so only a slight reduction. I believe that is in the acceptable range for this engine, but perhaps someone here knows otherwise. Again, its the old L head, cast iron engine, model 326437.
At this point, I am quite certain the problem all along has been what I didn’t want. That being the ignition coil is needing replacement. As mentioned up thread, the coil on these engines is located inside the flywheel, necessitating the engine be pulled entirely from the tractor to access the flywheel shroud, then the flywheel, and the cold sitting smugly beneath it.
I have done this coil replacement job myself in the distant past on the original engine. Were the engine a lightweight, I would probably sacrifice a day or two to do the job myself again. But, I’m not getting any younger, and this engine is a monster, totally cast iron brute of an engine, requiring an engine crane/cherry picker to lift it out. But, that’s only after having to remove several other major components on the tractor/traction unit before lifting the engine out.
Feeling benevolent, it may be time to share the joy of pulling one of these with the small engine mechanic who was eager to take the job on. Besides, he’s all of 40 years younger than I am, so he likely needs another horror story to share with his buddies anyway. I’m headed his way tomorrow morning to leave it with him. Over the phone, he was confident he could whip the coil out and have a new one back in and the tractor running fine by the next day. Um, that could be optimism talking, but then again, maybe he’s right on. We’ll know more in a few days. I don’t plan to pick up the tractor for at least a week, to make certain he’s had plenty of chances to work it hard to be sure that replacing the coil is the solution. Keeping my fingers crossed!