Mott 72 Flail Mower sparking and throwing belt

[pmsmechanic]

If you are getting sparks you should be able to see where the flails are hitting the frame/shroud. Also the should be visible damage to the flails.

I'm wondering if the "bent wheel" is from camera lens distorting the picture. If it is bent a bit it's not going to affect the mower operation.

 

[TerryR]

I'm wondering if the "bent wheel" is from camera lens distorting the picture.

That's what it looks like to me.

 

[jonsstihl]

mine does vibrate a little as It goes up the range from idle to PTO RPM but it smooths out at full speed. I think you have found your problem. Here is a helpful PDF about mott 60 & 72 inch models

whoever said to remove the blades to test has never done it. there are 184 stations it would take forever and them you have to put them back on.

 

[jonsstihl]

his mower does have a rear roller as well. it appears to be in the second picture. they do cut better the lower they are set.

 

[PanarchyMills]

Thanks for the replies and for that pdf. yeah, I just finished replacing all the blades and am not about to take them all off again. I have it set up on v blocks with a dial indicator and I'm trying to straighten the shaft by heating the high sides with an oxy-acetylene rosebud (like I read that they do in shaft straightening shops), and I've been strategically smacking it with my sledge. I've been able to get it from 0.20" out (+- 0.10) to about 0.030 (+-0.015), but it's hard to measure perfectly because the surface is pretty rough. I'm going to try to pop it all back together today and give it a whirl and will update if that worked

 

[leonz]

Please spend more time with the torch as it is still MUCH, MUCH, too far out of round.

 

[jonsstihl]

plus one on the trying to get it closer. that is a lot of weight to be that far out at the RPM it spins. It should be better since it started out at .200" but vibrations will kill a flail mower fairly quickly. plus it is a lot of work to get it all back together only to find out it has to come back out.

 

[PanarchyMills]

Re-measured and it was a little better than I had posted, and surface roughness is easily +-0.010 on this, so I called it good and put the cutter shaft back on and it runs very very smoothly! She cuts amazingly well with the new cutters and runs smooth at PTO 540. Here's a video I took running it through 5-foot tall rye cover crop (

). The mower isn't vibrating in the video, it's just bouncing and my filming is jerky.

Thanks for the help diagnosing this - especially the advice to put a dial indicator on it. For anyone with a similar problem, following the procedure that shaft straightening shops use with spot-heating along the high spot and checking round with a dial indicator and v-blocks (I used wood) seemed to do the trick, along with some strategic whacking with a sledge.