International c3 mower belt wont stay on

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donnyG
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Tractors Owned: 1955 International Cub Lo Boy
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International c3 mower belt wont stay on

Postby donnyG » Sat Apr 29, 2017 7:40 am

Hello. I'm brand new to this forum. I recently restored a 1955 cub lo boy and procured a international c3 mower deck. The old belts that came with it were in fair condition so I used them when I started mowing last year. The long drive belt eventually disintegrated late in the season so I purchased a new one from a Farmall dealer using the belt numbers on the old belt. The new belt keeps coming of during operation. I suspect I'm not getting the belt adjustment right but from pictures of this deck I have seen I may have the belts on the wrong pulley. I am using the bottom pulley for the drive belt and the top two for the right and left blades Does any one know if this is a factor and the correct order for the belts?

Scrivet
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Re: International c3 mower belt wont stay on

Postby Scrivet » Sat Apr 29, 2017 1:04 pm

Left side on the lower groove, Right side in the middle groove, Top to the rear for the drive belt. Assuming the pulley (sheave) height on the spindles are set correctly.

JohnMihevic
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Re: International c3 mower belt wont stay on

Postby JohnMihevic » Sat Apr 29, 2017 1:12 pm

Welcome to the Forum!
I have a 1948 Cub with C3 mower. The drive belt from the PTO pulley goes on the top pulley sheave on the center spindle. The left spindle pulley (left as viewed from sitting on the tractor), goes to the bottom pulley sheave on the center spindle. The right spindle pulley, goes to the middle pulley sheave on the center spindle. Depending on how the left and right spindle pulleys were put on may affect which center spindle pulley sheave you use. My left spindle pulley is about half way down the spindle shaft and the right spindle pulley is at the top of the spindle shaft. Try to get the belt to the spindles as close to parallel to the mower deck that you can . The main drive belt up/down/tension adjustment is via the two direction changer pulleys (at the rear of the tractor) that take the drive belt off of the PTO drive pulley.

Hope this helps,
John M.

Edit--I guess the answer came in while I was typing.

donnyG
Posts: 28
Joined: Fri Apr 28, 2017 7:17 pm
Zip Code: 05753
Tractors Owned: 1955 International Cub Lo Boy
Location: Vermont

Re: International c3 mower belt wont stay on

Postby donnyG » Sat Apr 29, 2017 5:23 pm

Thanks John M. I'll get the belts running on the correct pulleys and hope They stay put. I bought a new belt just because mine had jumped off so many times. It was getting ragged in a few spots. Does your mower have any belt guides on it anywhere? My deck has none and this could be an issue too.

SONNY
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Re: International c3 mower belt wont stay on

Postby SONNY » Sat Apr 29, 2017 6:20 pm

If it has a 3160 deck, there are NO idler pulleys on them.--the belts tighten by loosening the spindle bolts and pry the thing out til belt is tight.--gotta have correct belts, as there is not much slide in the deck. thanks; sonny
Image

tst
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Re: International c3 mower belt wont stay on

Postby tst » Sat Apr 29, 2017 8:25 pm

there is suppose to be a belt guide that bolts on to the rear bolts for the center spindle, the idle pulleys on the mule drive should be with in one inch alignment of the center pulley on the deck

JohnMihevic
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Re: International c3 mower belt wont stay on

Postby JohnMihevic » Sat Apr 29, 2017 8:38 pm

donnyG wrote:. . . Does your mower have any belt guides on it anywhere? My deck has none and this could be an issue too.


My mower has no belt guides. I think the reason your drive belt was jumping off was that you were on the mower center spindle bottom sheave instead of the top sheave. My "direction changer" idler pulleys are in a long slot with a lot of adjustment. My "rough" adjustment is to position them so the belt is parallel to the mower deck when the mower is down (this will line up the drive belt so that it will not be going into the sheave at an angle and be less likely to jump off). Then I "trim" the adjustment to get the right belt tension. I would take a picture, but right now my mower is off the Cub since I am replacing a cracked torque tube housing.

John M.

tst
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Re: International c3 mower belt wont stay on

Postby tst » Sat Apr 29, 2017 9:52 pm

if you look in the manual section on this site on page 5 for the C3 mower you can see the belt guide

donnyG
Posts: 28
Joined: Fri Apr 28, 2017 7:17 pm
Zip Code: 05753
Tractors Owned: 1955 International Cub Lo Boy
Location: Vermont

Re: International c3 mower belt wont stay on

Postby donnyG » Sun Apr 30, 2017 6:07 am

Thanks. I'll check it out. I found the manual but the pic is very dark. It describes where it attaches so I'm going to make one. Hope it works because the grass is growing an inch a day now!

donnyG
Posts: 28
Joined: Fri Apr 28, 2017 7:17 pm
Zip Code: 05753
Tractors Owned: 1955 International Cub Lo Boy
Location: Vermont

Re: International c3 mower belt wont stay on

Postby donnyG » Sun May 07, 2017 6:33 pm

Thanks everybody for your help. I correctly positioned the sheaves and put the belts on in the correct order. First trial the drive belt stayed on but then the left belt broke. I needed new ones anyway so I ordered them. They came and I put them on and mowed for 45 minutes with no issues. The manual was a great help as well. I'm still not sure if my particular model had a belt guide but I made one with some flat stock and positioned it as in the manual. Figured I'd try everything. I really appreciate the help guys. Great forum!!!


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