I need a deck belt for a cub cadet 2166 what length is the belt

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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the original length of deck belt is Deck Length 96 1/2" Type Covered Width 1/2". Fits Model. CUB CADET : LT1040 and LT1042, 42" ...
and pls vote me as helpful if it is

TractorData com Cub Cadet 2166 tractor information

Cub Cadet 2166 engine

Cub Cadet2166Parts Diagrams

Download the owners manual from Cub Cadet using model number 13A-244G100.

Customer Service Cub Cadet

Pages 41-43 might help:

http://www.manualslib.com/manual/33969/Cub-Cadet-3184.html?page=41#manual

powerwash the whole unit,make sure there is no build up on the head of the motor and all the fins around the motor,make sure that the heat deflector is installed properly,(Cub CadetKH-12-029-04
Adapter, Carburetor), #5,also be sure to clean the spindles and under the mower deck,also make sure the blades are sharp,grease all fittings,if the mower turns freely then there is less effort by the motor,
here is the parts list for the mower,http://www.partstree.com/parts/?lc=cub_cadet&mn=2166+Tractor ,

replace that safety switch there is two switches built into one

did you check to see if your belt was in good shape and if the hydro relef was in

Visit this web site http://www.partstree.com/parts/
you can pull up your Cub