Why does my mower kill the ignition?

Question edited to fix all the spelling errors.

An engine needs 3 things to start.
Fuel.
A spark at the right time.
Compression.

One is missing. Lots of troubleshooting help in the videos.

https://www.google.com/search?q=John+Deere+737+won%27t+start

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Your question is convoluted... is it a no crank or a no spark or both? Both, implies brake switch but can be other.

I find no detailed free wiring diagrams so I can answer only in general.

For engine crank, most ZTR mowers require brake ON, PTO OFF, and both steering arms OUT (ground drive neutral), then ignition switch to start position. Some ZTRs require operator in seat in addition.

As for spark... engine ignition kill shunt circuit will close to battery negative (frame ground) when ignition switch is in the off position, otherwise open at ignition switch. Safety circuits operate in parallel to the ignition switch.

When ignition switch is not in the off position, the following safety circuit conditions will close the kill shunt.

1. PTO on and operator not in seat.
2. Brake on and either steering arm out. (Most but not all ZTRs).

The incomplete diagrams I find show a relay that powers the starter solenoid so verify relay not energizing and trace back through safety circuits. A simple inexpensive automotive test lamp would be a useful tool for troubleshooting.

The seat switch energizes the operator presence relay which prevents the brake switch from connecting the ignition kill circuit to battery negative when brake is disengaged.

z425 shows ignition safety logic is as follows;

Engine RUN if Seat Occupied or Brake ON and PTO OFF.

Symptoms imply seat occupied circuit is OPEN. Check seat switch/wiring.

ZTR mowers will kill the engine if the operator seat is not occupied and the brake is released. Likely you have a failed seat switch but could be other... it will depend on the particular Toro model.

this sure sounds as if you have a seat switch issue , this is a safety device to make sure theres an operator that weights more than 115 lbs in seat , the blade engauge problem and non movement tells me this

check the "kill switch" they are usually located in the seating area. it senses for pressure or seat angle and will kill the mower if nobody is sitting on the mower. Good Luck

Remove the carburetor cover and observe the action of the carburetor throttle arm as you actuate the throttle. If the arm doesn't move, disassemble the throttle trigger assembly (making part placement notes as you do so) and clean out any accumulation of sawdust/dirt. Make sure the cable or rod which connects it to the throttle arm will move--there should be spring return of the throttle arm to idle position. If this fixes the throttle problem, but the kill switch still doesn't work, you may have to remove the left side case to access the ignition module and the kill switch wire which plugs into the end of the module. The switch itself may be full of sawdust as well preventing contact to engine ground. Hope this helps!

sounds like to me you have a bad seat swicth ive seen that befor

check switch on brake