racerone, thank you for sticking around. This story is so long.
I'm short on the diagnostics. Timing, stator signal, trigger and crankcase pressure measurement techniques I'm not familiar with. I'll have to look for videos on how to.
1 Spark at the right time
One of the big clues I have is that even squirting premix into the cylinder it does not fire. If I have compression and spark and the timing is on (if this were any other engine on my stand), then some shot of fuel should/would make it pop, even if I had to pull 10 -12 times to get past flooding. I would expect some sort of reaction. And I get nothing. This has to be the super-clue.
I also gotta learn how to diagnose signals from the stator and magneto coils to the power pack. Is the input right? Is the trigger jumping? How do I know my flywheel magnets are good?
The amount of spark energy jumps a 3/8"air gap and several spark plugs light up the night. I will say the upper spark plug wire and boot does not leak like the lower cylinder's. When I pull the lower spark plug lead while running I have to really get the wire away from the block or it'll keep arcing wildly to grounds. Without the spark plug lead inserted, the coil for the lower cylinder will arc to ground. The top cylinder wire and boot does not leak anything wildly to ground. Better insulation? Weak? If weak, would it jump 3/8?
I've swapped all spark plug leads and coils. I have not swapped the flywheel, trigger, magneto coils, stator or power pack.
2 Compression
Consistently tests at 125 psi. The lower cylinder tests at 120. Could be off gauge-to-gauge but the ballpark is believable. If I throw an error of 30 psi at my reading and look at either 155 for the high or 95 for the low, the 155 doesn't seem likely and the 95 might still work so I gotta believe compression is actually between 110 and 135 psi. I think it's good.
3 Correct amount of fuel
This is where I went down the rabbit hole with reeds (but I'm still stuck with the squirting premix dead reaction from above). Without splitting the crankcase I cannot get to them. If all other attributes are in line, then I'm not getting fuel. Squirting premix should support that and it doesn't so I flirt back to timing. What would stop fuel flow to just the top cylinder? Reeds not articulating, intake cover gasket leaking at the upper position. Any other independent pathway for just the top?
Originally, I found the carburetor needle sticky. Cleaned it up, went through the jets, etc, did not change any parts. It's the Walbro carb with the little coil spring on the bottom of the needle. The carburetor is wet and dumps fuel out the front when choked. Adjustment will influence the running quality. Seems to be functional to where I should be able to run and deal with tuning. Squirting premix should give me a reaction and it doesn't.
4 Crankcase compression
Reeds, bearing o-ring, crankshaft seals, covers and gaskets. Cracks? Is there any way to measure crankcase pressure?
Of course I'm stuck with not knowing when to quit spending money on it or diagnostic stuff. Who said "it's not the destination, it's the journey"? As a learning experience it has yet to pay dividends. I hate to junk it because so much of it is good. There has to be a solution but right now I do not have the diagnostic capabilities.
Thanks for listening and for the support.
J
