Compression Release only affects compression when starting. Change your Fuel and Air Filter, then drain Float bowl.
You may need to remove emulsion tube and clean out all jets.
Be sure that the belt is the correct WIDTH as well as length. I just restored a LA125. Belts also wore through the guards. I pop riveted a piece of SS on the outside. Some shields had a metal pin in them to stop this. The squawk might be from the Clutch. Try the old PTO cable if you still...
Remove Fuel tank Cap and fuel line at filter. Blow back the line carefully with minimum pressure. Do this outside, off the driveway and don't be looking in the tank while you do it. Then blow the other direction using low pressure. If fuel flows OK, continue to removing Float bowl and be...
Disconnect the present Battery and try a known Good Battery. Engage Parking Brake, handles in Start Position.
Then start checking safety switches. No stuck plunger etc. Check Battery Ground to Frame.