You really should pull the deck and give an inspection. One needs to know that the spindle bearings are not binding, the tensioner and idlers move freely etc Belts simply wear as well and you may want to compare it to a new one. It is possible too that the belt has hopped one spindle pulley and is dragging on the spindle housing.

I have a LT1045 and my blades will stop turning when I go faster and when I drop my deck down to 3 it will stop turning all together

suspect either a damaged/stretched deck drive belt or a sticking pivot for deck takeup idler.

Pivot plate is spring loaded. With engine off, chk plate for free movement and clear of trash. If plate moves freely thru it's full range, then chk deck drive belt for being stretched too far.

There is one other possibility. If the bolt holding the blade to the shaft became loose. the blade would be free spin independently of the shaft. In this condition I would suspect that just because of friction with the bold the blade would start spinning, but when it hit the grass it would stop.

If it were mine I would immediately check both bolts holding the blade to the spindle. (Or what ever the mechanism was that served the same function)

You could have a similar situation with similar results if the pulley on the spindle became loose on the spindle. ie miss key on the shaft?

My mower will bog down but the motor does not bog down

lt1045 carries a 3 blade 46 inch deck. Smithallen indicates entire deck is slowing down under load, but engine is not....correct?

That is correct.when you put the deck down in 3 it will bog way down

then, smithallen885, look for problem in either deck belt stretched too long or spring loaded idler takeup pulley pivot bar is sticking and letting belt be slack. If neither of those things, then electric PTO itself may be slipping - very unusual.

The deck design on these mowers must have been drawn up by some 3rd grade elementary school kid.. Stupidest things I have ever encountered.

Remove the deck, then the belt.

Remove the idler tension springs.

Remove the bolt that holds the idler pulleys to the deck.

Move pulley A as far back as possible without it hitting the belt where it passes to the rear of the deck. WELD IT in place.

Reinstall the the front idler pulley. Make sure it moves freely.

Reinstall the tension spring.

You will need another belt other than the factory size (off of the top of my head,can't remember the size).

Reinstall the deck and a new belt.

Problem solved.

bullhockey welding? Bwah- Hah-Hah-Hah.....

Bent PTO engaging handle. Causing slack in the system when you engage mower blades. I bet your handle wont fully move into the off position. It stays about halfway. So when you engage, it's not fully engaged. That metal arm is junk and easy to bend. Bend it back and possibly change PTO cable and I bet the farm it fixes it.

Just a word about slipping belts on a deck that is low to the ground------ I watch a lot of U tube videos and have come across ( Grass Rats ) mower repair shop in Indiana. There is a lot of tongue in cheek comedy but then they show a serious video. Any way that was the situation and Taryl took the tension spring off heated and bent a hook into it closer to the center of the spring and he says it works fine

OK. I'm having a similar but opposite issue. When the deck is raised high (8) the blades spin slowly. If I lower the deck to (3), the blades spin faster and I can mow. Seems opposite of the complaint which started this thread. Also, when I mow, the left most blade (3 blade Cub Cadet) doesn't seem to cut as well and I'll have to mow that area again making sure it gets hit by the center blade or right blade. All 3 blades were recently removed and sharpened and the balance was verified. The blades were put back on in random order. The mower was doing this prior to removing and sharpening the blades. Are these 2 related (I think they are) and what's my next move to fix it? Model RZT-L54 (17CRCACA009). Thanks!

My zero turn troybuilt will drive fine when it’s on. But when I engage the blades sound like they are spinning to fast? could it be a belt

Agree with the bend pto handle. It doesn’t take much to bend it apparently. what I have to do every once in a while (still trying to get it fixed) is with the mower off, engage the blades. detach the mower safety button (you might break it otherwise) then put a block of wood about a 1.5” between the brass handle button presser and the black frame. Then disengage the blades and pull the handle back hard until it bends.

i keep having to do this so I don’t know if there’s too much friction or something in my deck, but this is what works for me.