Yep. And there's this to internalize. When you troubleshoot, assume nothing. The combustion tripod stands on three legs: ignition, compression, and fuel. You can directly inspect the ignition, and until you do you're chasing your tail. You can directly inspect compression. You can only assess fuel mixture indirectly unless you have an exhaust gas analyzer and a dynamometer. The rule of thumb is "When in doubt, ignition first." Troubleshooting is a process of elimination, not a guessing game, and I kick myself every time I forget that principle and spend a few hours running in circles.
