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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
#11
NorthBama
was the engine unbolted to get the old belt off if so was it fastened back in the same spot. Sometimes when the pulley is rusted on the engine shaft i unbolt the engine from the frame and slide it back to clear the belt keepers. This would make the belt loose if not back in position. Just searching for clues. looks like the belt is routed correct.
I replaced the original engine with a 14.5HP Briggs OHV. Same bolt pattern.
#13
NorthBama
that may be the problem the old engine may have had the center line of the crankshaft closer to the front of the frame just saying i dont know for sure. I ran into that issue when replacing a single with a twin cylinder engine
Well it looks all good to me except that engine pulley.
It could be the flash from your camera but it looks like the pulley is polished right down to the root.
If this is the case the belt will be running too deep which will cause the belt to be slack
I would like to see the first image again (111720) again with the pedal fully backed off and the pedal fully down
Does the Belt have tension on it at all? From the pics it looks like it does. Might have a keyway in the axle missing or sheared. But not sure if that one has it in them.
Well it looks all good to me except that engine pulley.
It could be the flash from your camera but it looks like the pulley is polished right down to the root.
If this is the case the belt will be running too deep which will cause the belt to be slack
I would like to see the first image again (111720) again with the pedal fully backed off and the pedal fully down
I installed the engine pulley from the troybilt bronco and made no difference. The mower starts moving when the pedal is pressed around half way and doesn't really speed up no matter where the engine speed is set.
The belt is 90 1/2 inches long, I'm thinking of buying a MTD belt that is 89 inches long part# 954-0341.
Thanks for the photos & the video.
But please focus the camera and put it on something solid as they were all way out of focus.
The pulley on the left is worn out so you can toss it for starters.
The pulley on the right does not much better but it is hard to tell as all of the close ups are fuzzy.
From the video the tensioning arm operation looks good
So you are either down to the front pulley is too worn or the belt is too long.
And I will put money on the front pulley.
V belts drive from the sloped sides so if at any time the inner face touches a pulley it holds the sides off the pulley causing the belt to slip.
Both of those pulleys appear to have polish marks on the curve at the bottom which means the belt has been running too deep.
The wear on the drive pulleys is typical of what you see when some one fits standard section belts which is common because they are 1/2 the price of the proper belts.
Is there any reason why the brake linkage is hanging down ?
I had another pulley laying around and it wasn't polished looking but still did not help. You think the lower belt is to short? Not to long? I bought the correct OEM belt. Though I'm really tempted to buy a shorter MTD belt to see if it helps.
I disconnected the brake rod because I've been testing out different things and no reason at the moment to connect it.
Brain fart should have been "too long"
Went back & edited it to read correctly
The correct sized belt in the correct unworn engine pulley sits about 1/16" inside the rim when there is 3 belt keepers so it can not fall off.
On mowers where the engine pulley has just a bolt as a keeper the belt sits deeper to stop it falling off when slack.
Belt 954-0341 codes out to a Gates 85890 which is 89.15" x 5L listed as a vari drive belt so it should fit.
But it looks like you will really need a belt closer to 2" shorter which would be a Gates 6988.
Belts are a nightmare with old mowers because there are so many things that come into play
Fitting shorter belts is my fall back and down here it is a lot cheaper that replacing the front pulley.
As previously mentioned those pulleys look bad and they look bad on the video of the mower running as well.
Of the 2 the new belt will be the cheaper , just bear in mind that if you do replace the pulley that belt will not fit.
A reasonably common repair that comes into the workshop because the customer has gone to the MTD shop & been quoted $ 500 for the repair.
Because the franchised dealer can not fit shorter belts so he has to replace all of the pulleys so the mower can run a std belt.
Old mowers are a bigger problem because you never know what has been done to it before and all of the domestic mowers have a 1" drive shaft so any pulley could have ben fitted.
There is an old after market pulley catalogue here that lists 276 different stack pulleys
Tried a 88" belt and it's to short. It works but it's always spinning the transmission. I don't know if a 89" would work or not now.
*EDIT* Took back the 88" belt and got a 90" belt and it still drags. It seems like the engine pulley is fine as it's catching very easily. Also with a shorter belt it still isn't going fast as it should.
When you fitted the 88 " belt did you back off the control rod to compensate for the shorter belt ?
Were the other belts 5L profile and not std 5/8" B section, it makes a big difference ?
As for the front pulley.
It does not make a wrinkled rats rectum how well the belt picks up on the pulley.
If the pulley is worn then the effective diameter is smaller thus the belt speed will be lower so all things being equal, the mower will always run slower with a worn drive pulley.
And not trying to be picky, but bend the retainer tabs back square to the frame and pull the pulley stack down to swap the belts .
A new pulley will have the belt running flush with the outside edge of the pulley.
It might be worth while to slip under a new one sitting in a showroom and take a few photos of the front belt.
The troybilts have cruise control so you can lock the drive pedal down to tension the front belt.
Be naughty , go to a different shop & act like you are thinking about buying one
Because the sides of a pulley are sloping it is hard to evaluate wear from just looking at them.
Get a thin drill bit and lay the shank end across the working face of the pulleys.
The open area under the drill bit is the wear.
On the variable pulley, the sliding sheave can wear in an almost step like fashion and these tend to prevent the sliding sheave moving properly up & down the axis.
You can tell a person who uses cruise control because it accelerates the formation of steps in the pulley.
The actual speed of the mower is nothing more than the differences in the effective diameters of the drive & lower variable pulley and the upper variable pulley and the tranny pulley.
The belt length makes no difference provided it is short enough to get the sliding sheave to the limit of its upward travel .
Now if you want to get your head around this calculate the circumference of a drive pulley starting at 4" diameter in 1/8" diameter incriments then multiply this out by 3600 ( engine pulley speeds ) to give you inches of belt travel / min
You will see the difference between 4" and 3.875" is massive so a small amount of wear in the drive pulley will make a big difference to the final speeds.
Most of my customers are trying to save money so I consider a pulley worn out when the root is polished because in that condition it is not transmitting full power to the belt.
There is a big difference between worn and worn out.
Your friendly MTD dealer would have replaced the engine pulley and the variable speed pulley and probably both idlers and the tension arm, fitted a new standard belt then relieved you of $ 500 and your mower would drive like new.
And if that is what you want that is what you have to do, end of story.
From your original post I thought you just wanted the mower to run so you could cut your grass , not make the mower run like new.
