Troy bolt riding mower model a13039 mower deck doesn't engage when I got switch qa

Check (compare) the left and right rear deck lift links. Likely one has become detached or otherwise is loose.

See Cutting Deck Removal in Service section of your owners manual.

https://www.troybilt.com/en_US/prior-year-models/bronco-bronco-42inch-troy-bilt-riding-lawn-mower/13WV78KS011.html#/Troy-Bilt/13WV78KS011_Bronco_(2014)/Frame%2c_PTO_%26_Lift/205ecc55-4004-487c-ba7c-45eec1ba0efb/893227c6-4841-40b6-b0b5-58f600cc7df9/y

Riding Mower Electric PTO Clutch Won't Engage When Hot ...

? 7:16
www.youtube.com/watch?v=wH9tZl6GzE0
May 2, 2014 - Uploaded by Steve O The PTO is relatively easy to change assuming that you can get the bolt out of the crankshaft. Basically follow ...

there is a safety switch that may be out of adjustment when you engage the deck

sounds like wrong belt you raise it belts tighter lower belts looser or the tensioner has come loose

There is a spring attached to a tensioner that probably came unhooked while changing the belt. Higher deck settings push the deck backwards enough to spin the blades, the lower setting need the spring tensioner to take up the slack in the belt.

If you lower the blade deck and get down near the mower, you can see the blades belt on top of the deck. If it is intact, with the engine off, have someone try to engage the blades. A tensioner should move into place to tighten the blades. If it is not, follow the engagement lever to under the dash to see if there is a cable broken or a rod detached.

Post back.
Gary

Here's the diagram for that mower, I'm assuming the deck belt broke : http://www.partstree.com/parts/?lc=troy_bilt&mn=17AA5ABP766+RZT+50+%282006%29&dn=769021650003
Belt is 134" x1/2" Troy-Bilt# 954-04044A

One or more of your drive belts is in need of adjustment or replacement, maybe. Possibly, your electric (or manual) PTO clutch could also be adjusted. You do have the spring tensioner on the deck engaged, right? You say the engine doesn't bog when this happens so I am inclined to think "clutch" and/or "PTO belt" to the deck and/or the "deck tensioner" are the things to check.

The tensioner will be the easiest, it is a handle on the left side ON the deck. Has a BIG spring on it. Make sure it is engaged.

Is yours a Troy Bilt manufactured in Troy New York or is it another manufacturer (MTD?). Troy Bilt is actually out of business, having sold the Troy name to a variety of makers depending on the model line. I don't have the run down on who makes what any more (tillers, chippers, mowers, blowers, trimmers, etc.), but Troy Bilt of Troy, NY is no more. :-(

I have a 16 HP Troy with 42 inch deck driven through a electric clutch. I also have a "grass pump" on my deck. Important maintenance tips: Keep the bearings greased, keep the deck clean underneath. The belt on the deck should have the tensioner released when you are NOT mowing. Keep the blades sharp and in good repair. Mow with engine at full speed. When you get to areas of heavy growth, slow the tractor down (hydro drive) or reduce to a lower gear (gear drive). NEVER adjust speed using the "clutch" (hydro drive or gear drive). When you engage the blades (electric or manual) always have the engine just above idle, bring the engine speed up slowly to preserve the belts and reduce stress on all components.

I am sure this is the fix for your trouble. If there is anything else or if I missed the ball, please let me know and we will go further.

Thanks for your question @ FixYa.com

check your drive belt, it is different then the deck belts, as it is above them