YTH20K46 Mower Drive Belt Too Long

[Skywatcher]

Greetings All

Have a Husqvarna YTH20K46 lawn tractor ( Spec 960430033-03 S/N 021209B001604) in my shop and the belt is too long. Customer supplied OEM belt P/N 405143 which I measured 104¾". Part number on decal in hood says primary mower belt should be 532 40 51-43 and Partstree says the same belt should be 584 45 31-01. All these numbers cross ref to Stens P/N 265-106 which Stens say should measure 105¾". Even with the OEM belt measuring 1" shorter than what Stens say it should be, the belt is way too long for this tractor/mower deck combination.

Has anyone else run into this problem, if so, what length of belt worked for this tractor? Is it possible that this may not be the original deck that came with this tractor? The customer also says the belt that was on the machine before it came in kept coming off and eventually broke, so don't have it for measurement. With this tractor having a 20 hp engine and a 46" deck, what are people's thoughts on installing a ⅝" belt of the appropriate length onto this unit? Thanks and all the best,

Sky

[38racing]

My aftermarket same as stens. both numbers 105 3/4. Is it possible routing is wrong or a pulley has been changed to smaller size?

[hanz63]

It all seems right. I wouldn't use a 5/8 myself if felt I needed to change the spec as this is a manual engagement. Really the things I look at for not keeping tension are checking the spindle legs for breaks and so often the front support bracket gets punched back creating a mess plus a real positive rake. 46's have a larger spindle pulley than a 42. were they switched? Or a smaller fixed idler was installed? Cable tension should be lax, but quickly ready to engage.

[KE4AVB]

It all seems right. I wouldn't use a 5/8 myself if felt I needed to change the spec as this is a manual engagement. Really the things I look at for not keeping tension are checking the spindle legs for breaks and so often the front support bracket gets punched back creating a mess plus a real positive rake. 46's have a larger spindle pulley than a 42. were they switched? Or a smaller fixed idler was installed? Cable tension should be lax, but quickly ready to engage.

Some good possibles. Personally I had no problems with the deck setup here.

As for using 5/8 belt I would need to look at the spindle pulleys here to see they would accept the 5/8. I just don't remember ever thinking about that as an upgrade on a Husqvarna. I have however done a MTD here that I personally use and it works but sizing is critical. I had to I was killing the poor 1/2 belt with that 21 hp engine that I replaced the 16.5 hp with. I reckon that what I get for cutting 12" or higher grass with a 42" deck. I actually got a standard Kevlar Husqvarna belt on it now. Does have a tendency to throw the belt on engagement if I raise the deck with I first start using the mower. After the belt warms I have no problem engaging the deck.