I have a lth120 riding mower every time i try to engage the mowing deck or release the brake the engine quits

Safety and Preparation Serious injury can occur if the engine or mower blades accidentally start while you are working with lawn tractors. To prevent this, drive the Murray lawn tractor onto a flat work surface and disengage the mowing deck cutting blades. Engage the parking brake to keep the mower from moving; chock the wheels with a wooden block or brick. Adjust the mowing deck to the lowest position. Turn off the engine and remove the key from the ignition. While not necessary, you may even wish to disconnect the spark plug wire from the spark plug. Mowing Deck Removal You must remove the mowing deck on a Murray lawn tractor to gain access to the belts. Remove the adjustment rod hairpins, followed by the adjustment rod pins from the front left and right sides of the mowing deck. At the rear on the left and right sides, pull out the retaining hairpins and slide the mowing deck suspension links from the adjuster plates to separate the rear mowing deck from the frame. Remove the blade control rod stud, including the hairpin and washer, from the top of the blade control lever shift linkage at the left rear of the deck. Remove the front hanger rod, including the hairpin and flat washer that hold the rod in place. Loosen the belt guide retaining bolts with a socket wrench and remove the engine stack pulley belt so you can slide the mower deck out from under the tractor Transmission Drive Belt Installation Slide the new transmission drive belt between the engine stack pulley belt guides, over the belt guide plate and under the engine stack pulley. Fit the transmission drive belt around the top engine stack pulley. Push the free end of the transmission drive belt up through the transmission shifter hole in the lawn tractor floorboard. Slip the transmission drive belt loop over the transmission shifter. Pull the transmission drive belt down through the transmission shifter hole. Fit the transmission drive belt around the transmission drive pulley and tighten the transmission drive pulley belt guide retaining bolts to hold it in place. Fit the transmission drive belt flat side around the idler pulley. Slide the idler pulley onto the idler pulley stud while holding the belt in place. Tighten the transmission idler pulley retaining nut with a socket wrench to secure the idler pulley to the idler pulley stud. Mowing Deck Drive Belt Installation Pull back on the right side mowing deck mandrel pulley spring-tensioned belt retainer. Guide the new mowing deck drive belt around the right side mandrel pulley and release the belt retainer. Pull the drive belt spring-tensioned retainer away from the mowing deck idler pulley, guiding the deck drive belt around the idler pulley. Fit the mowing deck drive belt around the left side mandrel pulley and under the rear mowing deck cross link rod between the right and left side mandrel pulley. Slide the mowing deck under the right side lawn tractor frame, reconnecting the deck to the frame in reverse order of removal. Engage and disengage the mower deck while driving the mower to test the belt for proper operation.

sounds like a bad switch. unhook and check them (seat brake and deck)

ck your occupant (seat) switch it might have gotten dislodged or unhooked when fueling it

The first thing I would check is to make sure the drive belt is not binding somewhere.

you have a bad seat switch

Engine oil level.battery connections.

Hi and welcome to FixYa, I am Kelly.

The power sequence for engaging the blade deck is. Clutch brake pedal depressed, operator in seat, Enage selected and brake pedal released. When the blade enages the engine igniton kill wire is routed through the seat switch AND the PTO clutch. If either the PTO Clutch or the seat switch has a problem the engine dies. Same goes for the clutch brake pedal switch... if the clutch brake is not coming all the way up the engine will die.

If you respond with a model number (example LX2000) I can show via a manual where you need to troubleshoot using a meter.

Do a couple of good bounces on the seat, check the clutch brake pedal switch for clicks and then attempt to an engagement.

Also inspect the PTO clutch wires and connectors for corrosion.

Thanks for choosing FixYa,
Kelly

were you mowing at the time? if you didn't disengage the blades, the engine will not start, everything will seem "dead". if that's not it, check for a blown fuse

maybe the safty switch under seat might be starting to go out if that switch doesn't work the blades wont come on at all for safety

Try putting a jumper wire on the wire going from the engine to the seat. Take that plug and put a wire from one side to the other. Be careful not to cut your feet off when engaging deck.