Deck belt question

[dhoadley]

I threw the deck belt (runs the 3 blades) while cutting with the A/C917. 42" deck. What came off was a 3L84. Couldn't find one at the auto store but went with a 4L85. Looks like a perfect fit. Which one is right? Thanx, Dave

[deebig]

I think you made the correct choice. 3L belts are 3/8" wide vs 1/2" for 4L. Unusual to see a 3L belt on a mower.

[MARK (LI)]

I needed a belt recently and called Jack's...the guy was extremely helpful...told me where to get the #s he needed and sent me a perfect fit

[PhanDad]

The newer 42" decks with the splined arbors call for a 84.1" HA arbor drive belt .  

The older 43" FDT decks use an 82.1 HA belt.  

 

[dhoadley]

21 hours ago, PhanDad said:

The newer 42" decks with the splined arbors call for a 84.1" HA arbor drive belt .  

The older 43" FDT decks use an 82.1 HA belt.  

 

This one must be older; no spline shaft.

[MrSteele]

The splined shafts were an improvement. My deck has 2, both on the outside. The center shaft is the older style, with 2 bolts holding the blade on. Was going to replace the center shaft with the newer splined shafts...cost is a bit prohibitive! I had a local machine shop make me a new center shaft, made it 1 inch longer than original for the proper installation of a nylock nut, or 2 jam nuts. The nylock stopped the always loose locknut situation on the center shaft. The shop knows me. Every time I go through the door, they ask what kind of old lawnmower I am working on now!

I updated the deck to a spring loaded idler from the fixed idler. That changed the belt length, Brenda sent me one, that has been there for a while. I still have the old Kevlar belt from the fixed idler. It will likely work, and will be tried when this one dies. The spring loaded idler situation needed a longer belt

[kwt]

9 hours ago, MrSteele said:

I updated the deck to a spring loaded idler from the fixed idler.

I've never a fixed idler. Is that for something ancient?

[PhanDad]

3 hours ago, kwt said:

I've never a fixed idler. Is that for something ancient?

Very early decks: 

Part #15 was manually adjusted in a slot in the deck that can be seen in this IPL:

  

 

[kwt]

Seen.