MTD smoking drive belt

darrinster

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MTD Model 13AH660F016

I replaced the rear drive belt. When I try and drive it the Front drive belt starts smoking and there is a screeching sound.

I took the variable pulley off and got it working great but still does the same thing. Also you have to put it in the highest speed for it to do anything.

The belt I purchased matched with this number MTD 9540370. 5/8" x 48" (45" inside measurement)
 

ILENGINE

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First check to make sure the parking brake down by the right rear tire isn't stuck in the on position. Also MTD require that you replace both belts at the same time because they have to sync to work properly. Also you have to use OEM belts because not original belts don't work or last very long.
 

bertsmobile1

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I don't normally do he "me too" bit but I will second this opinion.
Belts must be replaced as a set.
Belts are a unique cross section being shallower than a normal belt for the width.
If you put a standard sized belt in then the inner face of the belt can bottom out when the pulley is at its smallest diameter
 

darrinster

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Just put on new belts and I'm still having problems. It's like the front drive belt is to long but it's the correct belt.

I tried adjusting one of the rods that connects the foot pedal to the variable pulley but it didn't help much.

Should I buy a smaller belt?
 

bertsmobile1

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Measured back to back is the original belt shorter than the 2 new ones ?
That would be the only reason to put a shorter belt on.
Belt lengths and widths are critical on these sliding sheave drives
The belt is screaming and smoking because something is preventing the double pulley from turning so the belt is slipping.
As it is screaming & smoking this tells me that the tensioning spring is working properly so either the double pulley is jambing or the axel is jambing.
Slip the rear belt off and try again.
If the front turns properly with no screaching and smoking then the problem lies between the double pulley & the wheels.
Does the mower push freely when in Neutral ?
 

darrinster

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Measured back to back is the original belt shorter than the 2 new ones ?
That would be the only reason to put a shorter belt on.
Belt lengths and widths are critical on these sliding sheave drives
The belt is screaming and smoking because something is preventing the double pulley from turning so the belt is slipping.
As it is screaming & smoking this tells me that the tensioning spring is working properly so either the double pulley is jambing or the axel is jambing.
Slip the rear belt off and try again.
If the front turns properly with no screaching and smoking then the problem lies between the double pulley & the wheels.
Does the mower push freely when in Neutral ?

Rolls freely in nuetral.

When I took the old belt off I compared it with the new one and it was the same length just not as stretched out.

I actually have another MTD identical to this one and I can't see any difference in the mechanisms to be causing the issue. The front belt does not get tight until you put it in the highest gear.
 

bertsmobile1

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If it helps you get your head around things, the whole thing works by varying the tension in the front belt which works against the tension in the rear belt.
The rear belt tension is trying to push the sliding pulley down and is balanced by the tension in the top belt trying to push the sliding pulley up.
The rear tension is fixed by the spring under the seat and the front belt by the bigger spring under the axel.
Moving the speed selector alters the balabce between the two so the slider moves changine the drive ratios.

Something is stopping this happening.
If the back turns freely without the front pulley on and the front belt drives happily without the rear on then the sliding sheave itself is the likely suspect.

You can download the MTD manual from here
mymowerparts.com/pdf/MTD-Service-Repair-Manuals/
You are looking for the "Must Have Book 2"
 

darrinster

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If it helps you get your head around things, the whole thing works by varying the tension in the front belt which works against the tension in the rear belt.
The rear belt tension is trying to push the sliding pulley down and is balanced by the tension in the top belt trying to push the sliding pulley up.
The rear tension is fixed by the spring under the seat and the front belt by the bigger spring under the axel.
Moving the speed selector alters the balabce between the two so the slider moves changine the drive ratios.

Something is stopping this happening.
If the back turns freely without the front pulley on and the front belt drives happily without the rear on then the sliding sheave itself is the likely suspect.

You can download the MTD manual from here
mymowerparts.com/pdf/MTD-Service-Repair-Manuals/
You are looking for the "Must Have Book 2"

Got it driving!

Stupid me had the rear drive belt routed wrong around the shift lever lol

After that it starter driving, still had slack. I lifted one front wheel onto a bucket to look under the mower and for some reason doing that caused the slack to go away.

Anyways, thank you for help!

Some pictures of the mower. In good shape for it's age.
0403161719-01.jpg0403161719-02.jpg0403161718-00.jpg
 
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