JD LT166 Mower Problem

[hotponyshoes]

Not sure how I got dragged into sorting this out but anyway..

John deere LT166 ride on mower,
Apparently had a full service before winter storage, came out, worked fine for half an hour, possibly "ran over a dog chew" and is now making a clanging noise.

I had a quick look and the blade tips are hitting each other as they rotate.
I would have guessed that the blades were supposed to be offset to each other so they don't interface? (Like a twin-rotor helicopter) but these are directly in-line.
They seem very firmly connected togeather, I'm guessing toothed belt?

Are they supposed to be in-line or offset?
Any simple way to adjust them?
I'm wondering if I can just undo the securing bolt on one blade and rotate it 90? Are the blades just clamped in place or are there location pins?

Also seems strange that it ran fine for a while? Maybe some stripped teeth on the belt but I can't see in there?

 

[Beanwood]

Assuming it’s the same as my LTR180 it’s a Toothed belt. They should be at 90degrees.
Take the deck off and undo the top belt cover- easy to see what goes on then- but the belt path is convoluted!

 

[Beanwood]

Toothed both sides by the way. Some pictures of mine done a month ago…

 

[Erie Fred]

I recall seeing the older Bolens having a drive shaft between the 2 blades, when this system died, some retrofitted
simple spindles with a V belt.
They simply ground the blades down on the ends to keep from hitting, had no problems with leaving an unmowed stripe in the middle.

 

[hotponyshoes]

This one is a 2001 machine, didn't realise it was more than a few years old as it's absolutely immaculate.

On the n/s of the deck upper cover there is a single 19mm nyloc, remove that and, with the deck dropped to the floor you can access the tensioner.
I loosened it off, rotated one blade 90deg and put it back together.
No missing teeth or even any signs of damage to the (new looking) belt.
Apparently all belts were done at the last service so I think it was reassembled with the blades directed wrong.

Started it up, made nasty rattle (although she said it was a lot quieter than last time) drove for maybe 20m before it lost drive and stopped.

That was the main drive belt come off.
On the rear axle there is a plastic fan between the belt and the hydrostatic? gearbox/drive unit. The blades of the fan have started breaking apart and catching in the belt chucking it off.
Can barely fit my chubby hands in there so I cut the remaining floppy blades off. The 2 remaining ones don't seem to be causing a balance issue

Not sure how much cooling the drive unit will need? OK to run it for an hour at a time without the fan? Or, Order a replacement? Looks like you would have to drop the rear axle to fit it...

 

[Erie Fred]

I would replace the fan, there is not allot of oil in there, and it's doing allot of work.

 

[Beanwood]

This one is a 2001 machine, didn't realise it was more than a few years old as it's absolutely immaculate.

On the n/s of the deck upper cover there is a single 19mm nyloc, remove that and, with the deck dropped to the floor you can access the tensioner.
I loosened it off, rotated one blade 90deg and put it back together.
No missing teeth or even any signs of damage to the (new looking) belt.
Apparently all belts were done at the last service so I think it was reassembled with the blades directed wrong.

Started it up, made nasty rattle (although she said it was a lot quieter than last time) drove for maybe 20m before it lost drive and stopped.

That was the main drive belt come off.
On the rear axle there is a plastic fan between the belt and the hydrostatic? gearbox/drive unit. The blades of the fan have started breaking apart and catching in the belt chucking it off.
Can barely fit my chubby hands in there so I cut the remaining floppy blades off. The 2 remaining ones don't seem to be causing a balance issue

Not sure how much cooling the drive unit will need? OK to run it for an hour at a time without the fan? Or, Order a replacement? Looks like you would have to drop the rear axle to fit it...

Ah sorry - I was in a hurry when posting earlier. I meant to say the first pic showed the tensioner at the top of the screen - that you can slacken off a bit.. Loosen that off and you MAY get lucky - and it looks as though you did - good result!

 

[Brad93]

you need to see if the timing has moved, lots of mowers now have blades whete they are synchronised so that you don't get a line of missed grass

 

[Turbo]

Here's a link to the service manual, there's a good guide to setting the timing belt.
https://www.gardentractortalk.com/d3/downloads/73599-Tm1695.pdf

I'm wondering if I can just undo the securing bolt on one blade and rotate it 90? Are the blades just clamped in place or are there location pins?

I used to service mowers for a living & every twin blade one with interferance blades had locating pins to stop this happening, something like this.

The ally pins locate in the blade & are designed to break off if you hit something hard, preventing damage to the blade.

I can't see anything like that on your JD but it should have something similar.

Not sure how much cooling the drive unit will need? OK to run it for an hour at a time without the fan? Or, Order a replacement?

The hydrostatic box on all mowers is the biggest weak point & when (not if) it gives up the mower is scrap, the box is too expensive to rebuild. So take no chances, get a new fan fitted asap plus change the gearbox oil while you're in there.

This one is a 2001 machine, didn't realise it was more than a few years old as it's absolutely immaculate.

Given the date it's probably one of the built in USA ones & they are very well made. More recently only the large commercial mowers are still USA made, the rest are made by Castel Garden in Italy & rebadged JD.

 

[Nomad]

@Beanwood that's the first time I've seen a belt that's toothed on both sides - every day is a school day

The last photo looks like one of those impossible Escher drawings - it looks like the belt has 3 ends

 

[Beanwood]

@Beanwood that's the first time I've seen a belt that's toothed on both sides - every day is a school day

The last photo looks like one of those impossible Escher drawings - it looks like the belt has 3 ends

Sorry about that - nothing quite so clever. My belt snapped, and I was just taking pics to remind me which way it goes back on, as it was going to be a week before it arrived....

 

[Turbo]

Sorry about that - nothing quite so clever. My belt snapped, and I was just taking pics to remind me which way it goes back on, as it was going to be a week before it arrived....

Even though I've fitted a lot of these belts I always do a drawing of the belt route under the belt cover using a paint marker.