Lawn mower deck vibrates and sounds real bad when you engage the blades

I was cutting a section in the way back that had over grown, not insanely but it had been blocked off for about 2 months so the grass was maybe 8 inches tall got into it several feet the lawn tractor started struggling for a second and before i could do anything the blades stopped turning completely even though they were engaged and a ton of smoke came out from the deck. Drove back onto the lawn and tried to engage them again and nothing, drove back up to the house and they did reengage but excessive vibrating and didnt sound good so i shut them off. Tried to engage them again a minute later and nothing. The engine sounds completely normal when the blades arent engaged. I backed the tractor up onto some car ramps i have and nothing was blocking the blades or anything. The belt was off on the right side (the side the grass shoots out). The belt has definite damage in an area and needs to be replaced, however with it being 9 oclock at night and all stores closed i reattached the damaged belt to try and identify if my only problem was the belt or something more serious. The blades now turn but the vibration and noise when you engage the blades is still there. I'll be picking up a new belt tomorrow but my question is could a damaged belt alone cause the definitely noticeable vibration and weird noise or is it likely something else is bent or damaged like say the crankshaft etc...?

 

It sounds like something may be still wrapped around the blade(s) shaft. You may have to remove the blades to check behind them. It may not be visible from the bottom side of the blade.

Also check for excessive free play in the blade shaft.
Possibly a bearing was damaged.

 

Thanks for the quick response man, appreciate it. How would you check for excessive play in the blade shaft? What would be normal vs excessive? I take it chances are the significant vibration and noise wouldn't be coming from the belt itself? 😒 its fine all over except 1 part that is hanging on by like 2 tenths of an inch, if that. Really hoping for something cheap that I can fix myself haha. Also not sure if this indicates anything but through turning the pulley that the belt was off i was able to get the belt back onto the pulley. Now I've never owned a lawn tractor before this one to work on but ive never belts on cars and trucks numerous times and thats just not something that you can normally do. Is that normal or does that indicate something else? It was hard to see in the dark like this but you could tell what i assume is the tension pulley moved as i was guiding the belt back on so its not like I slipped it on easy but i didnt need a wrench with a ton of force like all my car/truck belts ive done over the years. Just trying to include all possibly relevant info, thanks

 

The vibration is because there is a thin burnt spot in the belt from where it stopped and was smoking while the engine was running. This thin spot goes deeper down in each pulley as it passes around and then the wide spot comes and pulls back out to the outer part of the pulley and this continues around and around past every pulley at a high rate of speed, causing your excessive vibration.

 

Im on my way home from tractor supply, the specs online for the deck belt are 1/2 By 109" they didnt have a Toro replacement but they had one for club cadet that was for the same size deck but instead of being 109" it's 108 and 1/4. Would that work do you guys know? If I can get it on there would the extra tension damage it? Is there something I would have to adjust to make it fit without causing damage? They didn't have anything that was 109" so im hoping this will work as opposed to having to order one online and wait for shipping

 

I wouldn't bother even attempting to install that belt . . . . true, you might be able to accommodate that 1" difference in length if there's an idler pulley or clutch adjustment; but that ¼" thickness for a deck belt is pretty much unheard of. All of my deck belts have been ⅝ ".

For the amount of work involved in changing belts, whether they're the correct belt or the wrong belt (and in this case, you already know it's wrong) . . . . I'd rather you wait and find a supplier who can sell you a belt of the correct length and thickness; preferable an OEM belt.

 

I made that look weird the way i typed it. It's the right thickness, its a 1/2 inch the same as all the ones they had for sale for the most part were 1/2 the only difference is instead of 109 it's 108 and a quarter long so its 3/4 of an inch short. Also theres no length measurement on the package so it 3/4 of an inch short based on us taking it out and running a tape measure around it. The ones they had for sale based on size only went up to 107 long so we took one that was for the same size deck as i have and measured it with a tape measure

 

What I'm wondering is if its similar to say a 2x4 where its not actually 2 inches by 4 inches so if when they say 109 inches long is it normal for them to not actually measure 109 long and thats why when we measured it twice it was roughly 108 and a quarter

 

Does your mower have an adjustment for varying belt lengths ?

One of my mowers is an MTD that doesn't have an adjustment . . . . it expects the exact belt to be mounted in order to drive the blades without any slippage AND then also fully disengage. It's totally intolerant of improper belts.

I didn't see where you identified the make and model of your mower ?

 

It would help if you posted the make and model numbers.

I have never seen a mower made since 1980 that allows adjustment for varying belt lengths. I have seen adjustments on the spring tension er that allows for adjusting the tension on the Proper OEM belt or to aid in changing the belt. Neither have I seen an OEM belt of standard non fractional length, despite the fact that some auto parts and belt suppliers will sell some as such...
There is more than just length and width in reality when measuring belts, there is an outside diameter, inside diameter, outside width and inside width which determines the angle and length of the V which determines how they grab on the pulleys.... (some old Murray's I think may have...I digress)

It will also make a big difference depending on if you have a manual or electric PTO.

 

This is my first riding lawn mower so I've never worked on one including this one other than blocking the metal plates that kill the engine if you get off the seat. It was used when i got it. It's a Toro lx425 the part number for the deck spindle belt is 1125800. But no stores have that, id have to order it online and wait for it to ship. I didnt have time today to try the new belt after I got it so the plan was to get under the tractor tomorrow afternoon and see what i could do with this belt unless you guys are saying definetly dont do that and order the oem one online and wait. My thought at the store was that maybe they just shrink a bit or the tolerance on production isnt that strict so id give it a try. I dont want to damage the tractor by trying this belt as opposed to waiting a few days. Thanks for the responses guys.

 

It's a manual pto, there's a lever you push up about 110 degrees to engage the blades forgot to include that in the last post

 

Right now I'm not sure about what adjustments there are, ive never taken it apart. At 10 oclock last night in the dark i removed the safety cover to allow my to get to the belt and pulley that it wasnt on anymore. It was still on the rest of them.. I started to guide it on there to see if it would since it was so late. As I pulled at the belt and tried to guide it back on i felt what i could only assume was the tension pulley moving that allowed me to get it back on. Like I said before ive changed a lot of belts on cars and trucks never been able to do that before idk if thats normal on a tractor or not. It wasnt super easy to do but i was able to do it.

 

So these are a few pictures to better explain it. The one I got is a club cadet belt for 2 tractors one of which is 95404045

I found an oem online that is for a number of tractors, including my tractor and club cadet 95404045. So they would be the same belt then as far as I can tell.

 

So these are a few pictures to better explain it. The one I got is a club cadet belt for 2 tractors one of which is 95404045

I found an oem online that is for a number of tractors, including my tractor and club cadet 95404045. So they would be the same belt then as far as I can tell.

 

Ok so i went ahead and changed the belt. Trying to get the nerve to start it up and engage the blades to see what happens. Im worried though because 2 things youll see in the pictures below. 1. Despite the fact that it's 3/4 of an inch shorter than what it should be the belt seems way too loose up by the engine pulley, that much slack cant be normal can it? I feel like it would regularly just fall off the pulleys when engaging and disengaging. 2. That metal bracket in the other picture is touching the belt, not by much but it is touching the belt (That photo is when the pto is engaged) when its not engaged its not even close to touching it but when you engage it moves the other pulley bringing the belt in contact with the metal bracket. The metal bracket does seem to be slightly bent in and blackened where the belt contacts the bracket, like it should be there or has been like that for a while. Wouldn't that damage the belt? That doesn't seem right to me. Maybe I'll get the courage to start it up and just see what happens before I get an answer...thanks for the responses so far guys, love this site.

 

Do you have an Owners Manual for that rig ?

 

Many years ago I had a Dynamark lawn tractor. It also had a manual PTO engagement. The belt needs to be loose when the PTO is disngaged, otherwise the mower deck would always be engaged, albeit slightly. On my Dynamark, there were two metal "rods" that were parallel to the motor shaft (perpendicular to the belt), one on each side of the motor pulley. The rods were adjustable and, as I recall, sat approximately 1/2 inch or so from the pulley. The purpose of the rods was to prevent the belt from falling off the motor pulley when the PTO was disengaged. I assume that your Toro has something similar.

With the engine not running and the PTO engaged, is the belt tight against the pulleys? If so, then it probably will work correctly. One thing to check before you start the engine. With the engine off and the PTO disengaged, see if the blades turn without too much resistance. As Pete pointed out, there could be grass wrapped around the blade shafts.

 

Decided to start it up, just got finished cutting what i couldn't cut the other night, it sounds and runs beautiful. No problems at all and cut a decent bit of grass. No smoke, no burning rubber smell, no vibration, no noise. She's back to her previous beauty.

I dont have an owner's manual since its used but there is a downloadable one online i bookmarked for future use.

I did check before starting it up and the belt was tight with the pto engaged, just seemed a little too loose when it wasnt engaged but with all the guards and brackets that hold it on after thinking about it I'm sure it wont come off, I was just nervous when i first put it on.

I also engaged and disengaged the pto numerous times just to be sure it was good to go and it worked perfect.

Thanks for the help guys i really appreciate it.

 

Just to show you guys, this is what the belt looked like where it was damaged. Not sure how it stayed together at all haha. The rest of the belt is fine. The resistance of the high grass mustve caused a slip in the belt.