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James W
James W, Small Engine Troubleshooting Expert
Category: Small Engine
Satisfied Customers: 3708
Experience:  7 years as Mechanic & Parts Manager for Brother who has Owned Lawn & Garden Repair shop for 35 years
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How can I tighten the belt on a McCulloch Lawn Tractor Model

Customer Question

How can I tighten the belt on a McCulloch Lawn Tractor ? Model #M115T92
Submitted: 8 years ago.
Category: Small Engine
Expert:  James W replied 8 years ago.

HiCustomer Thank you for asking your question on JustAnswer. The other Experts and I are working on your answer. By the way, it would help us to know:
-Could you explain your situation a little more?


Which belt are we talking about?

Drive belt, deck belt, etc?

Thank you again for trusting us with your problem. Please reply as soon as possible so that we can finish answering your question.

Customer: replied 8 years ago.
Hello James,

I think it's the called deck belt. It's the one that drives the two blades.

Mick Wilson
Expert:  James W replied 8 years ago.

Ready for wierd answer number 500?


First go to the husqvarna web site. And down load this owners manual.


Yes, I know it is written in swedish... (Not a Joke)..


Go to page 59 and page 60 and find YOUR particular mower deck.


It could be 42, 36, or 32 inches.


Make sure the pully system and bracket system is the same as on your deck.


Zoom into 300% so you can see all the detail...


1. Make sure that you have the Belt routed exactly through the same path as is on the picture.

2. Make sure there is no obstruction keeping the idler arm from moving and taking up the slack in the belt (grass, sticks, dirt, etc get into the way sometimes keeping the spring from being able to pull it as far as it needs to move.

3. Make sure the sping is in good condition and is hooked to the right places to be able to maximize tension. (with out a good spring hooked the right place, you will not have enough tension and too much slack on the belt).

4. See if there is any way to adjust tension on the spring (I do not think there is, but put this in just in case there was a modification on your serial number that the photos don't show).

5. Examine the conditon of the Idler Pulley to make sure it spins very freely and does not wobble or have sharp edges. I woudl hate for you to have to replace a new belt because of a pulley cutting it or being worn.

6. If this does not solve the problem, the answer is to replace the deck belt.


REASON... These belts are in the shape of a V riding in pullyey that are also V shaped.

The belt rides on its SIDES in these pulleys making contact with the IN-sides of the pulley.

As the belt wears, it gets THINNER on the sides.

It therefore goes deeper into the V grove of each of the pulley's and in effect makes the Pulley seem Smaller in diameter. This effectively makes the PATH that the belt travels actually Shorter because it does not have to travel as far around each pulley (only an inch or two.

Ad to this that the belt does stretch a bit (only a tiny bit) and you have much to much slack.


So Often the answer to "How can I tighten the belt on a McCulloch Lawn Tractor" is

Replace the Belt...


Always see if you can replace the belt with the exact part number from the manufacturer. It will be the right length and be the right tension.


If you can not, make sure when they measure your belt, they adjust for the stretch and wear of your belt...


Good luck..

James W and other Small Engine Specialists are ready to help you
Customer: replied 8 years ago.
Hello James

Thanks for your prompt answer. Can I do all of this with the mower deck in place ? The view is not too good. Are there any parts I can remove to get a better look?
I shall click 'Accept' and trust you will answer my question.

Many thanks.

Mick Wilson
Expert:  James W replied 8 years ago.

You can look for trash and stuff blocking the movement of the idler arm etc with the deck in place.

You can check to see if the spring is hooked up right.


Almost everything else begs to be don looking at the mower OFF of the tractor.


This gives you a chance to sharpen the blades.

Clean under the deck.

See if there is any lubrication that can be done on the spindles.

you can not really check the condition of the idler with the belt in place because you can not see if it spins easily or wobbles.

You can not examine the condition of the bearings of the spindles very well that way either..

I would NEVER want to even try to change the belt with the mower in place.


Mer personally, I would have the deck off yesterday and give it a good once over especially if it sounds like it has been a while since it has been off.

In the long run, the time you spend on this Maintenance will be a good investment.


You could invest an hour here and save yourself te cost of 10 hours at your real job working to pay the bills that happens if you don't.


Enjoy your weekend.