Before you go any further I would whip out those guide plates clean them up & wack some paint on them.
I gather it gets a tad humid around your place with real cold nights & heavy dew.
SO some background might be good.
When did the engine last run ?
IS the loss of compression sudden or has it been getting harder to start for a while.
Also did you do the compression as per the manual.
You said you have worked on other engines so I hope that meas to rotated each cylinder to TDC compression before taking the readings & making the adjustments.
As for the plug, no colour is better than black.
If the engine is not running you will get no deposits on the plug.
If you have been cranking it for a while & it has not fired then the plug should be wet with fuel.
If not check the fuel cut off solenoid on the bottom of the carburettor.
If you get that much water in your rocker cavity chances are there is water in the solenoid & it has corroded closed.
Put everything back together so I’m gonna hold off on cleaning up the guide plates until I figure out if I have to break this thing down or not.
I adjusted the valve clearance at TDC yes, and triple checked them. Adjusted to factory specs. When I checked the compression I simply put my compression gauge and cranked the engine over a few times. I did this multiple times both sides. Not sure what or if there is any other method. But again it wasn’t a leak down test, don’t have the equipment for that.
Also pulled the carburetor and cleaned it, plus drained the tanks and cleaned them as well. The carb has fuel in it as it drains out of the bottom from the drain screw.
Both plugs are new. The left cylinder is showing light blackening from cranking the engine. The right has zero discoloration and I can smell fuel on it.
This motor was given to me and has been sitting for quite sometime and supposedly was running good but I don’t really know that for sure.
If I’m getting drastically different compression readings between the two cylinders, with any engine I’ve ever dealt with that would indicate something like a cylinder that needs to be rebuilt. Why would this engine be any different?
Thanks