Toro z5000 Blade won't engage

must you ask twice... replace the switch

replace the key switch then...

I would purchase a compression tester from auto parts store and check compression.

I’m happy to assist further over the phone at https://www.6ya.com/expert/layne_0fccff498c319c32

Is something Jammed into the Blade?

each lever has its own safety switch one of them has failed jumper each one to test them

Use a block of wood to hold blade stationary while tightening bolt. Ensure threads are cleaned with a wire brush before tightening. Is there a spacer or washer missing?

did the belt break or fall off? are the trans release levers pulled out ?the ones you release to push it around

if it has a electric clutch check for power to the clutch if no check the safety switches

Did you check under the deck for clogs? If its not clogged, DISCONNECT the spark plug wire, and try to turn the blade by hand... Oh yeah, did I mention DISCONNECT the sparkplug wire FIRST! If the blade won't budge, you might have a seized engine. If the blade does move, the problem is in the starter recoil. Rewind the starter string, and check the spring for damage. Good luck!

Hi and welcome to FixYa. I am Kelly,

It appears your model number is 74370 There are 3 bolts one for each blade and the part number is 26-0671 or 260671 for the blade mount.

Part look up:

http://www.jackssmallengines.com
then enter part number 260671 $6.31 ea.

You can not use just any bolt for this. They are hardened bolts with an NF thread. If you use a non hardened bolt the blade will fly off when the bolt shears.

This bolt is available at most all Lawn Mower Parts Supply sources. Toro uses the same bolt on most all of their mowers.

If you do not have a Lawnmower Parts Supply near by, you might be able to go to an Autoparts supply source with yet one of the other blade bolts in hand and have them match the markings on the bolt head with yours so that you have the exact replacement bolt.

Any other parts for your mower can be found here:
http://www.jackssmallengines.com/help.cfm

Use the Search model window. each line below is a drop down window
Toro
Riding
74370 <- there are numerous models up to 74704
enter your model number if different.

Thanks for using FixYa.

Kelly