No start even with starting fluid

[Vitokuz]

I have an older gear driven Murray 5.0, it turns over well, carb was cleaned and has spark but does not fire up even with starting fluid, it has fired for a second once but afterwards no matter what I try it won’t fire up again.

 

[bertsmobile1]

I they won't fire on a SHORT shot of starter fluid down the plug hole ( you can over do it & flood the engine ) then one of the following is the problem
This assumes that you do have a spark
1) spark out of time because the flywheel has spun on the crank ( key will be broken or cracked )
2) valves not closed
3)Piston not moving
4) Head gasket badly blown .

 

[slomo]

Air, fuel, spark and compression. Start with the basics.