Goes Great... But don't stop!!!

[Neo]

Hi All,

I am working on an MTD Yardman 604 (18HP B&S, Troy-Bilt Single Speed Transmission with Variable-speed Pulley) that has me totally stumped

When I first start up (and don't touch the Autodrive Pedal) I can select forward or reverse with ease as both drive belts are not moving. But as soon as I apply just a small amount of pressure to the pedal both drive belts start to move that make it hard to engage forward or reverse.

Now I would expect with the pedal all the way back (making the lower belt slack) that the belts would stop moving... but they don't..... Should they stop???

Then if I switch the engine off I notice the lower (longer) belt is firm (not tight) but if I give it a tug it goes slack and I can start the engine and the belt wont move again.

Or if, while the engine and belts are running, I move the idler bracket to make the upper (short) belt go slack both belts stop moving.

I think this points towards the Variable-speed Pulley but it seems Ok.... bearings/shaft are Ok and the sliding pulley disk moves freely up and down.

Also, I've just got this mower so I'm not sure if it's fitted with the correct belts ... how do I confirm that?

Thanks for your help guys
Neo

[Neo]

Does anyone have any thoughts on this issue?

[bcp]

Then if I switch the engine off I notice the lower (longer) belt is firm (not tight) but if I give it a tug it goes slack ...

What changes when you do that? And why does it seem to "stick" in the "belt firm" position?

Bruce

[Neo]

I can't see exactly what changes but I suspect it the centre disc in the Variable-speed Pulley moving away from the lower belt towards the upper belt.