Easy replacement. Comes with basic instructions. Fired right up. Our water heater had a good spark at the ignitor coil. It had good voltage at the wires when the switch was on. The 2 thermostats had good continuity when checked with a multimeter (ohms). So this was the last possible culprit before I just started hitting it with a hammer.

https://www.amazon.com/Atwood-93844-Water-Heater-Valve/dp/B0007XVWWU