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Discussion Starter #1
Got a stumper here, looking for input.

A buddy of mine has a Craftsman Hydro Lawn tractor ( Model 917.271141), & it's developed belt problems. He just bought it ( used) & it needed a GROUND drive belt, the old one broke.

He had someone throw on a drive belt & it broke after he started mowing. Actually it didn't break, it burned in half right at the engine pulley. He had the same guy replace the belt again, and the GROUND DRIVE belt smoked when he engaged the blades.

He brought it to me yesterday & I removed the deck,checked the movement of the tensioner puller, & the idler pulley on the ground drive, They are both fine. I lubed up any pivot points & installed the new drive belt. I test drove it around for about 10 minutes, going into forward & reverse and everything was fine.

I cleaned up the deck & checked the mandrels (they turn free), and the idler & tensioner pulleys, all is good there. I lubed up the pivot points for the tensioner & everything moves freely.

I reinstalled the deck and drove it around, engaging & disengaging the blades & everything worked fine. I called him & he picked it up last night, but then he called me first thing this morning & said that the new belt smoked, right at the engine pulley.


Keep in mind, this is the GROUND DRIVE belt burning when he engages the blades.

I'm stumped. The rear end seems fine, the input pulley on the hydro turns freely, and there is nothing binding or pinching the belt. It just seems strange to me that the transmission belt would smoke when the deck is engaged.

When he brings it back, I'll get some pictures.

Thoughts??


Dave
 

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Got a stumper here, looking for input.

A buddy of mine has a Craftsman Hydro Lawn tractor ( Model 917.271141), & it's developed belt problems. He just bought it ( used) & it needed a GROUND drive belt, the old one broke.

He had someone throw on a drive belt & it broke after he started mowing. Actually it didn't break, it burned in half right at the engine pulley. He had the same guy replace the belt again, and the GROUND DRIVE belt smoked when he engaged the blades.

He brought it to me yesterday & I removed the deck,checked the movement of the tensioner puller, & the idler pulley on the ground drive, They are both fine. I lubed up any pivot points & installed the new drive belt. I test drove it around for about 10 minutes, going into forward & reverse and everything was fine.

I cleaned up the deck & checked the mandrels (they turn free), and the idler & tensioner pulleys, all is good there. I lubed up the pivot points for the tensioner & everything moves freely.

I reinstalled the deck and drove it around, engaging & disengaging the blades & everything worked fine. I called him & he picked it up last night, but then he called me first thing this morning & said that the new belt smoked, right at the engine pulley.


Keep in mind, this is the GROUND DRIVE belt burning when he engages the blades.

I'm stumped. The rear end seems fine, the input pulley on the hydro turns freely, and there is nothing binding or pinching the belt. It just seems strange to me that the transmission belt would smoke when the deck is engaged.

When he brings it back, I'll get some pictures.

Thoughts??


Dave
Sounds like you did things the way they are supposed to be done. Now, since it is a hydro, I would try to figure out if the deck is being engaged while the tractor is moving or sitting still. I turn my mower on and off while the tractor is stitting still.

Is there an issue with the alignment of the pulleys? Are all the belts routed properly.

If the engine pulley is where the problem is then I would check the charge on the battery to see if it has enough juice to power the PTO electric clutch. Does the electric clutch test good?
 

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Does the tranny fluid need to be changed and it the outside of the tranny clean? Is it overheating?
 

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Discussion Starter #5
Sounds like you did things the way they are supposed to be done. Now, since it is a hydro, I would try to figure out if the deck is being engaged while the tractor is moving or sitting still. I turn my mower on and off while the tractor is stitting still.

Is there an issue with the alignment of the pulleys? Are all the belts routed properly.

If the engine pulley is where the problem is then I would check the charge on the battery to see if it has enough juice to power the PTO electric clutch. Does the electric clutch test good?
PTSW

The belts are routed properly & the alignment of the pulleys is good.

& this is a manual engagement on the deck, no electric clutch on this model.


I didn't check the fluid levels in the hydro, but it operated just fine, forward, reverse, up an incline & down, even backing up an incline, it was fine.


When I had it, I engaged the deck both sitting still with my foot on the brake & while rolling. No Problems.

The owner said he was sitting still withe the hydro in neutral when he engaged the deck.

Dave
 

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Discussion Starter #7
I guess this has happened before, here are 2 posts from a thread in another lawn forum, Both are from the woman with the problem mower.

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Post 1:

i inherited a 1990's craftman 25 hpv twin, kohler command 50 hydro cut. but....seems it had a history of the drive belt breaking whenever it was placed engaged. it would ride around all day like a golf cart as long as you did not try cutting the grass. 3 mechanics and 20 belts later i have gotten it. does anyone have this problem? did sears/craftman just put out a piece of expensive junk? i have looked at the alignment of the pulleys and they seem to fall in line. and the fact that it will ride me around all day just not cut grass is very confusing. Help help help


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Post 9 in the same thread, by the OP:

its the tractor drive belt that keeps breaking. the deck belts are fine. one belt to the deck, and the belt for the blades is fine. its the dang drive belt that breaks when i engage the blades. that is why its such a puzzle. new belts - not worn or frazzeled. it just eats new belts. got the deck off. now i just have to figure out whats causing the problem .

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sounds familiar. there may be an answer hiding in these posts.
 

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hmmm sound like a lemon lol
 

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Sounds like a person might want to try calling the factory and asking them what they can tell you. There might be a product recall or something with these belt eating mowers.

Like Bill said something about the engine being bolted down might be the problem. I have heard stories in the past about some bolts being left out on the assembly line and causing serious problems.

Maybe the frame or idlers are not bolted down properly. I would suggest reading the manual to figure out how it is supposed to go together and inspecting underneath the tractor for missing or broken fasteners.
 

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The question I'd ask is just what belt is being used as a replacement?

Make sure it's a belt designed for outdoor or agricultural equipment use, typically made of kevlar, which is more flexible, durable, and grippier than automotive, fractional horsepower, or industrial belts.

Also, pay special attention to all belt dimensions, including top (outer surface) width, bottom (inner surface) width, and height (er, . . ., thickness).

One factor may be the loss in engine rpm as the deck pulley grabs hold while trying to get the blade rotation up to speed. If the drive belt is driving the tranny and, all of a sudden, the deck is engaged slowing the crankshaft speed, the ground drive pulley will no longer match the speed being forced by momentum coupled from the tranny and ground drive belt. Kevlar belts will grab better and slip less than the others.

Just a thought to follow.
 

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Discussion Starter #11
The question I'd ask is just what belt is being used as a replacement?

Make sure it's a belt designed for outdoor or agricultural equipment use, typically made of kevlar, which is more flexible, durable, and grippier than automotive, fractional horsepower, or industrial belts.

Also, pay special attention to all belt dimensions, including top (outer surface) width, bottom (inner surface) width, and height (er, . . ., thickness).

One factor may be the loss in engine rpm as the deck pulley grabs hold while trying to get the blade rotation up to speed. If the drive belt is driving the tranny and, all of a sudden, the deck is engaged slowing the crankshaft speed, the ground drive pulley will no longer match the speed being forced by momentum coupled from the tranny and ground drive belt. Kevlar belts will grab better and slip less than the others.

Just a thought to follow.


The belt is a Gates blade Runner Lawn & garden belt & meets OEM dimensions. So I don't think that this is the issue. The first belt was the correct OEM belt from sears & the second was an L&G belt from lowes or home depot.

Also, on this, the deck engagement is by means of a hand lever, not an electric clutch so there isn't really a sudden load applied resulting in an rpm drop. It actually has very little impact on rpm when engaging at full throttle ( I know because I did it as a test).

what ever it is, it's drastic enough to burn thru a brand new belt instantly. Jeff said that when he engaged the deck it started squealing & smoking... and before he could disengage the deck lever, it had burned thru the belt.
 

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Check the routing of the blade engagement cable and lever on the deck in various height positions. My guess is something is hitting the drive belt when you engage the blades maybe only when the deck is in a certain position.
 

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Discussion Starter #13
Figured it out. The bolt that the idler / tensioner arm pivots on was loose & the hole was worn a bit. This let the tensioner spring pull the idlers down & out of line with the belt & causing the belt to wedge itself in between the edge of the pulley & the belt retainer.

I added a large washer below the arm to give it some support, bent it slightly to compensate for some wear in the mounting hole, bent the belt retainer in a bit (to keep the belt from coming so far out of the grove) & re-tightened & lubed everything & it worked fine.

The owner picked it up & called me the following day to let me know he had mowed 2 1/2 acres of nearly knee high grass with it, and it was working great.:thThumbsU


Thanks to everyone for their input.

Dave
 
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