question 79366 2 stage snowblower impeler broke?

[papadave 8]

just hooked up my 79366 2 stage snow blower and started it up and didn;t sound right,had wife come and sit on it so i could watch and the impeler is moving back and forth about a inch or so,tryed to tighten the 2 set bolts on it and its tight.the shaft is tight ,it doesn;t move .the key is still in the shaft so thats not missing.since i;ve never watch it running before,stupid question,its not supposed to be moving like that correct ?

[Lee1977 6,681]

My guess is the bearing is completely shot or has come loose to move that much. You'll have to take it apart to see what the trouble is.  You can find a parts drawing on " Parts Tree"..

[papadave 8]

29 minutes ago, Lee1977 said:

My guess is the bearing is completely shot or has come loose to move that much. You'll have to take it apart to see what the trouble is.  You can find a parts drawing on " Parts Tree"..

so there is a bearing inside the impeler ? 

 

[wallfish 17,023]

53 minutes ago, papadave said:

so there is a bearing inside the impeler ? 

 

No

Is the PTO pulley turning the belt when it's engaged? If so, you'll need to check the 90 deg gearbox, both the pulley and the sprocket and the chain. Then the bigger sprocket on the back of that impeller shaft that the chain goes to. Basically follow that entire drive train from the engine all the way through until the problem is discovered.

 

[papadave 8]

hi,you helped me last jan when my bearing went out,yes everything is working correctly,the bearing,small sprockets and chain are all new,its just like the impeller is loose,you can move it back and forth about a inch like it just needs to be tighten down to the shaft,can the 2 set screws tips wear down so its not holding in place ?

[Ed Kennell 38,326]

Is it possible there are double set screws in each hole like we find in some hubs?

Edited November 18 by Ed Kennell

[gwest_ca-(File Mod) 11,069]

Adding a second set screw to lock in the first is a good idea if done correctly.

The 2nd screw needs to have a flat face ground on it where it contacts the first screw. Eliminate the cup point.

If not ground flat the cup point enters the hex hole on the 1st screw and does a fantastic job of flaring the top on the 1st screw tight in the threaded hole never to be removed again.

[Wayne0 471]

7 hours ago, papadave said:

hi,you helped me last jan when my bearing went out,yes everything is working correctly,the bearing,small sprockets and chain are all new,its just like the impeller is loose,you can move it back and forth about a inch like it just needs to be tighten down to the shaft,can the 2 set screws tips wear down so its not holding in place ?

Pull the screws and look at the tips. They should be cupped.

Possibly the shaft is worn from improperly tightened screws. I'm not sure if there is flats on the shaft.

[wallfish 17,023]

6 hours ago, papadave said:

hi,you helped me last jan when my bearing went out,yes everything is working correctly,the bearing,small sprockets and chain are all new,its just like the impeller is loose,you can move it back and forth about a inch like it just needs to be tighten down to the shaft,can the 2 set screws tips wear down so its not holding in place ?

If it's sliding in and out on the shaft and the key,  it's the set screws not holding. Easy fix. Yes the point tip on them can wear and they don't hold near as as tight. The key should hold the impeller tight from spinning at all on the shaft and the set screws are there to lock it in place from sliding on the shaft.

 

[papadave 8]

took out the 2 set screws ( that was fun ) and they were badfull of gunk and thread worn away a little so it wouldn;t tighten down so ordered 2 new ones.my question is : if i want to replace the key,doesn;t really need to,would i have to take apart the whole shaft ? also what is the correct spot to tighten down the set screws ? do i push it to the wall or if i pull it towards me it goes to the end of key slot. thanx

[Ed Kennell 38,326]

1 hour ago, papadave said:

 do i push it to the wall 

Yes , just so it is not rubbing the back wall.

[OoPEZoO 525]

papadave hit me up to take a measurement of my impeller spacing via private message, but I wanted to put it out here as well in case anyone else ever needs it.  The face of my impeller is exactly 1/2" from the rear wall of the chute housing.  I'm assuming thats how it was initially assembled, as my tractor only has a little over 200 hrs on it and works well.

[Ed Kennell 38,326]

For any centrifugal impeller, water pump, hydro turbine, or snow thrower,  To operate most efficiently, the rotating crown or back plate should be aligned with the stationary discharge pipe or chute.   Any misalignment will cause a loss in efficiency.      On my Ber Vac, there is no rotating back plate, but the impeller must be close to the back wall to align the buckets with the chute opening.      Pretty difficult to get a good picture of this area.