How to tension alternator belt on ST185?

Some key details missing in the service manual on this... it says I need to set the tension at 115 +- 20 lbf whatever that means... it seems to assume I have some specialty gauge for this purpose, but not only do I not have one, none of the auto parts/tools shops in my area have even heard of one... so what's the procedure for correctly tensioning the alternator/accessory belt? Is there a way I can do it by deflection?

Second key detail not in the manual.... what is the correct torque spec for the tensioner pulley lock nut? the last thing I need is for it to come loose or for the bearing to seize up because I didn't use the right tension on it.

You loosen the 14mm nut on the pulley the belt goes around that's below the alternator then follow the long bolt that the pulley is on and you'll see a 12mm or 14mm nut facing the radiator on the end of that long bolt. You then turn that nut clockwise or counterclockwise to push or pull the pulley and that tightens or loosens the belt. Once you have the belt at the tension you want it at, tighten that 14mm nut that is on the pulley.
I usually tighten the belt until I cant turn the longest stretch of the belt more than 180* with reasonable force. If it squeals then tighten a little more until it stops.

lalojamesliz1":2zn07vik said:

You loosen the 14mm nut on the pulley the belt goes around that's below the alternator then follow the long bolt that the pulley is on and you'll see a 12mm or 14mm nut facing the radiator on the end of that long bolt. You then turn that nut clockwise or counterclockwise to push or pull the pulley and that tightens or loosens the belt. Once you have the belt at the tension you want it at, tighten that 14mm nut that is on the pulley.
I usually tighten the belt until I cant turn the longest stretch of the belt more than 180* with reasonable force. If it squeals then tighten a little more until it stops.

Click to expand...

okay so I have that much but what is the torque spec of the lock nut?

And is there no other good way to measure deflection?

Well on your first post you said the manual specifies tension at 115 +- 20 tension on the belt. I used to have a tool that measured belt tension. I threw it away when a friend told me the ways I mentioned.
Gates 91107 Belt Tension Tester https://www.amazon.com/dp/B000MUTAGS/re ... 6CbZZ457QN

Shade mechanic:

Press finger on scale until tension weight is obtained. Remember.

Press on belt until deflect and memory are obtained.

^ take scale when wife isn't looking
use scale to push piece of wood against belt until tension weight is obtained
sneak scale back to correct location