Small Engines (Lawn Mowers, etc.): Yardman mower, compression release, push mower

Question
I have a yardman 6.0hp 20-inch cut push mower. It acts like it wants to start but will not. Sparkplug is good, oil and gas is good. Blade keeps getting loose even after tightening and cord seems to be in on position and will not release

Answer
In will need additional information. Are you saying the pull start is locked and won't pull out? If this is the case it could be a number of reasons as to why. The rewind itself could be hung-up, you'd have to disassemble it to find the exact cause. Other reasons are as follows, 1. The blade brake on the side of the flywheel is not releasing when the handle is pulled. Check that the cable is pulling it from the flywheel.  2. Compression release is not functioning correctly, when starting there  is a gear in the sump compartment that releases engine compression when pulling the rope. Requires  removing the engine and then removing the sump pan and inspecting the compression release gear and parts. 3. Bent crankshaft, did you happen to hit something while mowing. 4. A seized crankshaft bearing. 5. Is the flywheel key partially sheared which could be causing you to be fighting the timing. As far as the blade keeps loosening, have you recently removed the blade? Is the trust washer facing the correct direction? Is the lock washer (if used) there? When you say it wants to start, what is it doing exactly?