What is this belt size, the one I got from sears tech is too big.Craftsman DGS 6500 pro 26hp, 48 deck.

Go to SearsPartsDirect.com they will help

https://search.yahoo.com/search;_ylt=Awr9DtuQ_u1a.McA_c1XNyoA;_ylc=X1MDMjc2NjY3OQRfcgMyBGZyA3NreWgEZ3ByaWQDSlBnR25VaFlSMnFEQzhJajVvNGNUQQRuX3JzbHQDMARuX3N1Z2cDMTAEb3JpZ2luA3NlYXJjaC55YWhvby5jb20EcG9zAzUEcHFzdHIDZGdzIDY1MDAEcHFzdHJsAzgEcXN0cmwDMzQEcXVlcnkDZGdzJTIwNjUwMCUyMGRlY2slMjBiZWx0JTIwZGlhZ3JhbQR0X3N0bXADMTUyNTU0NjY1NQR1c2VfY2FzZQM-?p=dgs+6500+deck+belt+diagram&fr2=sa-gp-search&fr=skyh&type=type90102-sv7-dGFnVzEyMjY1NTUtc2VhcmNoZWFzeQ-fd1827598aa83ce094266fa429a79a63 This is what I found when searching for the belt diagram.

get a spark tester and plug it into one of the plugs after it gets up to operating temperature. test the other one if you have good spark plugs and no spark going through the tester the coil may be breaking down. and needs to be replaced.

http://www.sears.com/craftsman-48inch-cut-lawn-tractor-engine-to-deck/p-07133907000P?prdNo=1&blockNo=1&blockType=G1

check with SearsPartsDirect

I WOULD SUGGEST HIGHLY YOU GET REPLACEMENT BELTS FROM SEARS . THE AUTOMOTIVE BELTS ARE IN ONE INCH INCROMENTS SEARS BELTS ARE IN HALF INCH .. GET YOUR MODEL NUMBER AND CONTACT YOUR LOCAL SEARS OR K MART . FOR THE PROPER BELT ! .. JUST THE WAY IT IS WITH CRAFTSMAN MOWERS ... SORRY ....

Thought I posted a solution earlier on this, but it was my first post and I don't see it here so I'll try again.
Google search on your model shows the drive belt diagram on page 27 of the manual.

link below:
http://www.mytractorforum.com/images/reference/dgs6500.pdf

Looks like mine.
basically need to remove front pulley by loosening center bottom bolt while holding the center nut on top of motor.
Slip belt over the rear pulley first and then straight toward the front, slip belt on front pulley and then slide pulley back onto shaft.
Then wind through the rest of the pulleys etc..as seen in the diagram.

You do not change the drive oil on these tractors. It is supposed to be good for the life of the mower according to sears craftsman.

i HAD SIMILAR ISSUES WITH MY 2500 SERIES CUB CADET....IT WAS THE CARB.....REPLACED, AND ALL HAS BEEN WELL...THINK IT WAS APROX 200.00

Hi
There is a pin in the back by the hitch - make sure it is pushed in. If it is pushed in then check to see if there are any oil leaks under it.