Lawn mower diagnosis 101.
Get an in line spark tester or better still a colortune and fit it
Get a can of starter fluid.
Remove air filter, give the mower a shot and try to start it.
If it starts but will only continue running is you keep giving it short shots of starter fluid the you have a fuel problem
If the colortune / spark tester does not flash or stops flashing before the engine starts to die, you have an ignition problem.
If you have a fuel problem the remove the float chamber and replace the cut off solenoid with a bolt/.
Engine runs OK the the solenoid or power supply to it is bad.
If the solenoid checks out OK the get a temporary fuel tank ( pinch it off your push mower )
Hook it directly to your carb and hold it as high as you can above the mower to give you the best head pressure.
Runs OK then you have a fuel pump / fuel line problem
No difference then you have a carb / manifold / valve problem.
Hook up the original fuel line again , start the engine & keep it running with short shots of starter fluid.
With a TRIGGER bottle of water/ Wd40 etc liberally spray all around the intake manifold.
Engine speed changes = air leak
Finally check the governor by starting the engine then hold the throttle open by moving the governor lever with your finger.
Works fine if you hold the lever open = governor problem
