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WMass713

Joined: Jan 24, 2012
Points: 3

Ariens ST724 Drive Issues
Original Message Jan 24, 2012 2:22 pm

I am having some issues with my snow thrower. Model # - 924075. Last week I started it and got it running good, however the drive didn't engage, I pulled the bottom plate and found the friction disk was not coming up to the wheel, also there seemed to be no movement when engaging the lever, today I pulled it apart and tried figuring out how to remove the wheels to try freeing them up as they are both in good shape, I couldn't figure it out, I did however adjust the tension nut to bring the friction disk higher up and applied some 3 in 1 to the shaft which appeared to improve the movement, I got everything working right by hand in the service position, but when I started it and ran it the drive wouldn't disengage and it's hard to shift between gears. Did I just over adjust the tension nut or is there a bigger problem? How do I remove the friction wheel assembly to lube the shaft better and will that help? Thanks in advance for any help.

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RedOctobyr

Location: Lowell area, MA
Joined: Nov 5, 2011
Points: 282

Re: Ariens ST724 Drive Issues
Reply #5 Jan 24, 2012 8:39 pm

The service manual will be a big help. It shows how to remove the friction wheel, etc. Also how to adjust the clutch tension (tighten it until the friction wheel just starts to drag, then back it off 3 turns, if it's like my ST824, 924082).

If squeezing the drive handle doesn't engage the drive, I'd do as trouts2 suggested, and trace through the linkage to see what's going on. If you can make the friction wheel drag by adjusting the clutch nut, then the aluminum plate is able to move closer to the friction wheel, like it should. So that's something. The friction wheel should spin when you turn the axle. The aluminum disk should spin when the engine turns. When you squeeze the handle, the two should come together.

WMass713

Joined: Jan 24, 2012
Points: 3

Re: Ariens ST724 Drive Issues
Reply #6 Jan 24, 2012 10:07 pm

trouts2 wrote:

For getting the friction disk to slide, clean the hex shaft with carb fluid and tissue or a rag. Then coat with lub, just about any. If your shifter is still sticking after that and your friction disk and clutch action are ok then ? Possibly your linkage rods are bent or something rusted or out of adjustment under the dash.

From what you said you did it would seem the issue is outside of the tractor base.

Ok, I must be referring to things by the wrong name, the friction disk I was assuming was the aluminum plate, the hex shaft is well lubed and the friction wheel (rubber coated wheel) moves back and forth easily with the gear selector lever. When it works right (which it did after I got it back from the shop 3 years ago) all gears match with selector position even with all the rust along the rods etc. I will try adjusting as suggested, and look up the service manual so I can figure out lubing the shaft the aluminum disk slides on a little better. Thanks all for the advice, hopefully I can fix it without paying a shop.

jrtrebor

Location: Michigan - 3 hours north of Chicago on the lake
Joined: Feb 10, 2010
Points: 539

Re: Ariens ST724 Drive Issues
Reply #7 Jan 24, 2012 10:37 pm

There is another issue that can cause your problem. Behind the belt pulley that drives the friction drive plate is a hub.
That hub needs to be able to slide freely. The shaft for the drive plate runs through bearings that are mounted inside
the hub. That whole unit moves forwards and backwards to engage and disengage the drive system.
(pictures below)
Dirt, grime and rust can cause the hub to bind up inside the sleeve. When you depress the drive handle the hub moves
backwards and the friction plate comes in contact with the friction wheel. If the hub can't move freely you can have problems
with the drive not engaging smoothly. And not disengaging when the handle is released.
Picture showing hub with blower housing and pulley removed hub is fully extended (drive disengaged)

Drive engaged postion

It's easiest to get to, to really clean and lube the hub assembly by pulling the blower housing. Then removing the large drive pulley.
It's a lot of work.
But I've also been successful curing this problem removing just the belt cover and working from the top.
It 's a tight place to work with the pulley and belts right there. But less work than
pulling the blower housing and pulley.

So I would just you try spraying some WD40 etc...Some fluid that is thin not thick like oil. On the top of the sliding hub and in the wide slots on both sides of
the hub sleeve. Then working the handle up and down. Tilt the blower back a little so the fluid will run
down into the sleeve. (Don't spray to much at one time) Also take a large screwdriver or pry bar and make sure the hub is fully extending out of the sleeve.
It may be hung up / stuck not fully extended. You can pry on the fork shown in the photo above. Then lube it and work the handle.
Also check to make sure that the tube the the fork is weld to is not stuck or binding up on the shaft that runs through it.
Everything needs to move freely. Or the spring tension won't be enough to release/disengage the drive.

So you don't get confused, this photo is of an old ST724 I have sitting around. There's no engine on it so you not seeing any
belts. The blower housing is just the shell so your also not seeing the pulley on the end of the impeller shaft.
Yours will look different with all those items in place. The hub is behind the large belt pulley in the photo.

This message was modified Jan 25, 2012 by jrtrebor

trouts2

Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1328

Re: Ariens ST724 Drive Issues
Reply #8 Jan 25, 2012 6:42 am

WMass713,

In this case having the names reversed described a different issue. Seems like a sticking drive plate.

jrtebor: "Also take a large screwdriver or pry bar and make sure the hub is fully extending out of the sleeve."

Yep, screwdriver under the drive plate with oil. I've had two in the past that were frozen and luckaly got them free without haveing to unbutton anything.

It's is a nice model with differential with an aluminum gearbox. Worse case is the gearbox could go which is $200 to replace but you get a nice gastiron gearbox. Most of the other parts in there last forever except a few springs and bearings which are cheap enough.

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