New Belt to long?

darrinster

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Bought a Craftsman made by MTD. 2011 model 247288841

Mower had a blown engine so I put another engine on it, same engine pulley and it goes slow in forward reverse is a little faster.

So far I have adjusted the foot pedal, replaced both drive belts and checked the variable pulley which moves great. Also brake pedal was moving the same time as the accelerator pedal.

The new belt has to much slack in it and there is not much tension on the variable pulley.

If not an actual tension issue, do you all think the transmission is done for? It was garaged kept no rust anywhere. The belts looked to be in good condition too, but I thought maybe they were stretched.
 

Rivets

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Two things come to mind very quickly. One, from experience you need to change both drive belts at the same time. Two, are you sure that the variable pulley is moving freely. They like to stick, which means you will have very little speed change.
 

darrinster

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Both belts replaced. The variable pulley looks brand new and moves quite easy. It's the lower drive belt that has to much slack even when the pedal is pressed. I compared it to another MTD I have with the same drive system. I fix and sell mowers on the side and so far have no had this issue. I try and stay away from MTD.
 

Rivets

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Belt numbers should be 954-04208 and 954-0467A. If you have the correct belts and the variable speed pulley is working smoothly, the next thing is the two idler pulleys and the idler arm all moving freely. There is nothing else in this system, unless you are missing or incorrectly hooked up one of the return springs.
 

bertsmobile1

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If the brake pedal moves when you depress the accelerator pedal then some thing is hooked up wrong.
The accelerator pedal makes the belt go tight & the bake pedal makes the belt go slack.
Tripple check the belt routing.
From memory that model has 2 flat idler pulleys on the tensioning arm so it is easy to end up with the belts running on the wrong side of the pulley.
As it is not your machine be warned that people do stupid things to "save" a few pennies.
Just took back a Troy Bilt with the same system.
Owner fitted a std V belt, because it is 1/3rd the price of a genuine MTD item then cut off the belt keeper at the bottom of the variable stack and fitted a guide on the tension side of the belt.
About as bright as a 2watt globe.
 

darrinster

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Narrowed the problem down to the variable pulley not rising up enough to allow for higher speeds. The idler arm bracket barely moves when you press the gas pedal. I removed the variable pulley and it seemed to move fine from my past experience with these. I went ahead and lubricated the center to just make sure and removed a light amount of surface rust that really wasn't even a problem.

Really stumped here...

*edit* Tried the belt from the other mower and still no go and it was even shorter. I guess it has to be the variable pulley causing the issue. Not sure why as it moves freely with no issue.
 
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bertsmobile1

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The system works by the accelerator pedal applying more tension to the variable pulley than the fixed tension applied by the spring on the upper belt.
If the lower belt does not pull tight enough the pulley can not slide up.
It will also not move unless the the pulleys are spinning.

Kevlar belts do not stretch so if the old belt is shorter than the new belt, the new belt is wrong.

The belts on the variable drive system are L profile so if you fit a standard A or B profile the system will not work either.
You have still not mentioned if you have fixed the brake moves with the accelerator problem.
As previously mentioned, the brake pedal makes the belt go slack.
So either you have routed the belt wrong or one of the pulleys is wrong/buggered or the belt is wrong or the belt adjustment is wrong or the pivots have flogged out oval.
 

darrinster

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Fixed the brake pedal moving with the gas pedal issue. Both belts are OEM MTD belts and routed correctly.

I swapped out the variable pulleys and still wont work. Could the spring for the upper drive belt be weak?

I'm at a loss on this, nothing seems wrong but still the variable pulley wont rise up enough to allow for full speed.
 

bertsmobile1

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IT is always hard to find mistakes with your own work.
And from the descriptions you have posted there is not enough information.
You also have things backwards in your head.

The top ( small ) belt is tensioned by a spring that pulls on the belt and forces the sheave down which makes the top pulley smaller which causes the mower to go slower .
So if you put the spring back in the wrong place for instance and increased the tension the mower crawls.

The pedal increases the tension in the lower ( long ) belt till it exceeds the tension in the upper belt which causes the lower belt to run closer to the axel of the varidrive pulley turning it faster and also pushes the sliding member up making the diameter of the top pulley larger which increases the belt length pre revolution so the top belt runs faster so the mower goes faster.
If the spring on the top belt is too loose them there is little resistance to pedal movement and the mower will only move fast.
Usually what happens is no drive till about 1/3 to 1/2 the pedal travel then no drive when the pedal is flat out cause the top belt slips under the extra load.

SO your problem is either too much tension in the top belt or not enough tension on the bottom, o r as you have to remove the top to replace the bottom both.

To take this any further we really need photos of the belt run on your mower and a link to the parts book for your mower so we can give you meaning full suggestions.
 

darrinster

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I attached pictures of how the belt is routed. The hanging rod is just for the brake it has nothing to do with the tension of the belt. One of the springs I don't have attached it's to help return the 2 idler pulleys.

It seems like the pedal has to travel completely down to put tension on the belt. The only adjustment I can see is the rod that goes to the gas pedal and it doesn't really help much when shortened.

Parts page of my mower https://www.partstree.com/parts/mtd...actor-2012-sears/transmission-drive-assembly/

One other thing: For some reason MTD shortened the upper drive belt by 1/2". The older models with variable foot pedal drive have the brake and gas pedal on one side, the model I'm working on are on opposite sides. Yet they both use the same lower drive belt which I think is to long as I can't find any obvious reason it's not working correctly.
 
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