My mower deck is not engaging. I took the deck off and made sure the brakes were not stuck, there is tension in the lever....what next

SOURCE: 320 john deere mower starts sputtering and pulling

How old is the battery, and is it in good condition?

SOURCE: John Deere ride on mower L100 17 hp.

my ride on runs well for 5 miutes then just stops wait a few minutes starts right up but does this over and over some help please

SOURCE: engaging the blades / PTO

There is either a yellow toggle switch or a yellow knob type switch on the dash panel that will engage your deck unless some of the safety switches are stopping it from working due to an adjustment problem or a defective switch,let me know if you need more help.

SOURCE: What causes JD 260 riding mower to start dying

It's the safety system that causes this. There is a switch under the seat that should activate when you are sitting in the seat. The switch can come loose or fail, the mounting can break, or the wires can come loose - any of these would cause the "engine dies when I engage the mower deck" behavior. Lift the seat, examine the switch. Rmove the switch and keep the plunger in with a piece of tape. Fixed? Then it's just the mounting or adjustment. Not fixed? It's the switch itself or the wires or connectors to it.

SOURCE: I just installed a 48"

study the photo in the webpage link as given below for towards the rear of the cutting deck you will see a left and right side support for the swing arms on the handle that slides into the eyelets of these 2 supports. the frong has two bars, left and right that attach to the front from the front axle area. locking pins hold these rods in place shape like a hair pin

https://jdparts.deere.com/partsmkt/document/english/featbene/fb_MaintSheet_LX178_48deckLawnTractor.pdf