Model 285 bush hog cutter

[Anonymous-0]

I have a Bush Hog model 285 that was donated to our churh and the gentleman said it sometimes has a vibration. i removed and checked the blades and they seem to be ok.I even weighed them and they are within 2oz.I did find that the blade plate has several cracks around the blade mountog holes and the holes are enlarged.If the plate had key way slots they are gone.Can this plate cause the cutter to vibrate sometimes?I was thinking about welding the plate but concerned about the mounting holes.
Any information will be most appreciated

 

[keh]

This is from my dealings with my Bush Hog brand rotary mowers:

On a Bush Hog there is a round disk called a stump jumper. Inside this there is a flat heavy steel bar with a hole in the center with a key way for the shaft from the gear box to go through. At the ends of this bar, which is welded to the stump jumper, there are tapered holes with a key way cut in them. The blades are held on by a tapered bolt which you have removed. This bolt has a key built in. If the bolt has the key worn off and the hole in the mounting bar is worn smooth, that would cause the vibration you mentioned. You will need a new stump jumper and new bolts. The stump jumper is fastened to the gearbox shaft with a left handed nut. You will have to turn the mower up on its side carefully and chain it to something so it wont fall on you to work on it. Good luck and be careful.

KEH