You should start your own thread.
"Thread Starter"
Adding on an old post only gets the mods upset.
The low comp is probably the gauge and not a real reading.
You pull all the plugs?
Timing?? What/ how did you set it at?
99.9% of the time, timing doesn't need adjusting.
The way the motors set up it doesn't change unless YOU do something to it.
The "idle" screws aren't idle screws they're air/fuel mixture adjustment screws for running at idle.
Missing at idle:Turn them(air screws) in till they just bottom out(gently) then out 1 and 1/2 turns till you can reset in the water.
Then while warm and in gear you adjust.
One of the top post is a linc and sinc. Do this and try to do the static timing.
Post your results.