Craftsman rider mower with variable speed pulley won't climb a mild slope.

[mouthman]

Hi,
My mower is a Craftsman LT 1500
I replaced the drive belt, and checked the variable speed pulley to make sure it was sliding and rotating freely.
The mower will jerk when I let go of the clutch quickly, so I am pretty sure there is no problem with the transmission but slowly looses speed until it stops.
No gear noise, no belt squeals.
If I try to drive up a mild slope, it will slow to a stop because the belt starts slipping.
I haven't figured out if there is an adjustment that I can do to tighten the belt and where to do it.
I have attached a diagram from the manual hoping someone can tell me if and where there is an adjustment I can do.
Thanks

 

[bertsmobile1]

The whole system relies on the strength of the spring # 27.
If it is weak or anchored in the wrong holes you aint going nowhere.
Next is the belts must be replaced in pairs
Finally the belts must be the correct profile & exact length
They are not standard B section belts .

The other thing to check is the root of the pulleys
If they are polished shiny that showd the belt is running in the bottom of the V and not gripping the sides so will slip

 

[mouthman]

The whole system relies on the strength of the spring # 27.
If it is weak or anchored in the wrong holes you aint going nowhere.
Next is the belts must be replaced in pairs
Finally the belts must be the correct profile & exact length
They are not standard B section belts .

The other thing to check is the root of the pulleys
If they are polished shiny that showd the belt is running in the bottom of the V and not gripping the sides so will slip

Thanks,
I will check tomorrow.
You answered a similar question a while ago and the spring for the clutch pedal was the problem.
I think I remember the pulley being shiny
I haven't replaced the upper drive belt.
Thanks again

 

[slomo]

Like Bert said, belts, spring and pulleys are the key to those working or not. Make sure you get OEM belts ONLY and a new #27 spring. Or go to Ace Hardware and get another similar size one and double up on springs.

slomo

 

[mouthman]

Thanks Bertsmobile1 and Slomo,
I fixed it
I checked the belt tension of the lower drive belt (spring 27) and it was fairly tight.
Then I checked the tension on the upper drive belt (spring 25) that pulls on the variable speed pulley and it was loose.
I could not get the spring to pull any tighter so I replaced it temporarily with a threaded rod which allowed me to tighten the belt a little more and now the mower climbs the slopes in my yard without a problem.
I don't think I can modify the old spring so I may have to look for a shorter one.
The mower however, does seem slow even at the highest speed, so I need to figure out where and how can I adjust for a slightly faster speed forward.
Thanks again guys!

 

[slomo]

Your pulley might be worn causing slow speeds. Again you might need to double up on the springs to get more tension.

slomo

 

[StarTech]

OR simply the variable to transaxle belt is worn out. It is the one that usually wears first.

 

[mouthman]

Thanks Slomo and StarTech,
You think there is a way to adjust the forward speed?

 

[slomo]

Thanks Slomo and StarTech,
You think there is a way to adjust the forward speed?

New OEM pulley and OEM belt is all there is.

slomo

 

[mouthman]

Hi guys, I do not know how to mark this thread as solved, but I went ahead and bought both belts and that solved the slow speed problem.
Thanks again!