42inch LT 2000, Kohler pro17OHV. What is the drive belt size?

The SV 590 is the model designation of the Kohler engine powering the lawn tractor.

https://www.google.com/search?q=kohler+model+sv590s+parts+diagram

The 'Sears 2000 Cub Cadet' part is most of your tractor model details and the Deck Belt appears to be 42".

https://www.google.com/search?q=Sears+2000+Cub+Cadet+deck+belt

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http://www.kohlerpower.com/home/home-generators/products?prodNum=12RES

Website shows 5 yr 2000 hrs. <?>.

V-belt Husqvarna part number is: 539117245 - about $50
No size is given.

Here is diagram: http://www.ereplacementparts.com/husqvarna-rz4623-ride-mower-parts-c-114486_117796_205921.html

remove the deck and give yourself some room to work

I just had a problem with my belts smoking also. Replaced belt and the same thing happened. Removed deck, flipped it over and their it was. I large stick had somehow gotten wedged between one of the blades and the deck frame, causing the belt to turn but the mandrel would not. Removed the stick and problem solved. I don't know if your problem will be solved as easily as mine but for me it was just a reminder to ALWAYS check the simple things (and normally the ones that doesn't cost) first and you may be surprised.

Cub Cadet has five models in their new Series 1000 lawn tractors, all powered by Kohler engines. Cub Cadet models -- as several other lawn equipment brands -- are manufactured by MTD Products.

The Cub Cadet LT 1045 has a 20-hp Kohler single-cylinder engine, with an aluminum block and cast-iron sleeve for longer life. It has a full-pressure lubrication system with spin-on oil filter for easier maintenance. This engine is not as powerful or as long lasting as the Kohler V-Twin OHV, which is available in other models in the line, but the LT 1045's engine is still solid enough to provide years of mowing.

The hydrostatic (automatic) transmission is a good match with the engine and provides sufficient grip to cut grass on moderate inclines. Power is transferred from the engine to the transmission by a heavy-duty Kevlar belt rather than a more expensive shaft drive. A Kevlar belt also drives the three cutting blades.

The mowing deck cuts a swath of grass 46 inches wide at one pass, and is removable for service and cleaning. Four anti-scalping wheels help keep the deck from scalping grass on uneven ground. The cutting height is manually adjusted from 1-1/2 to 4 inches. The turning radius is 18 inches, which standard for lawn tractors. This model is intended for use on 1- to 2-acre lawns without many turns or small obstacles.

is the drive belt off?

WHICH BELT ARE YOU LOOKING FOR A LOT OF AUTO PARTS STORES WILL GET THEM FOR YOU OR ORDER ONLINE. GET THE MAKE AND MODEL AND SERIAL FROM TRACTOR , BELTS SRE NOT HARD TO FIND

I believe they are 8mmX35mm.

it is a mtd mower ,however you should be able to go to a tractor supply store with the decksize and the engine size and get the proper belt.AGAIN(TSC) store,OR TSC.COM HOPE THIS HELPS