Can you tell me where the adjustment is for tightening the blade drive belt on a Murray 42" 17.5 hp rider mower?

Hi! reiter, welcome to AMHD :)

Adjustment is set with an idler pulley (sheave). It is either spring loaded and may have lost a broken spring or has a movable, screw adjustable pulley. The tension setting is usually about 10 lbs of force at the longest length of the belt or 3/4" of side deflection there.

But I also suspect an old or worn belt. Some questions to ask yourself:

How long have you had the tractor?
Do a lot of mowing?
Ever change the belt?
If you smell burning rubber, you could also have a frozen pulley (sheave).


k

Hi,
It is difficult to get ManualsOnline to work at the moment, but I did find a parts picture. The rod #18 threads into #33 and privides the adjustment.
Peace,
Clarke

Hi! Clarke,

There is a saying in a pastime that I thoroughly enjoy, Model Railroading,:

Don't nitpick a modeler about his layout, because somewhere, somehow there is a prototype out there.

Have a great day, Clarke!

Steve