I have a troy bilt 42 inch 17 hp lawn tractor. The problem is when I cut grass and i get in some thicker grass the blades turn off then I back out the blades restart. The engine never bogs down

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