Flail Mower Let's talk flail mowers

[JustBob]

The blades look good and th4 height is good so the other two parameters are RPM & ground speed. RPM need to be at 540 and ground speed needs to be less than 3mph (brisk walk).... IMHO.

As for the noise it should be a loud hummmm ... about 80db, but that also depends on how far you are from the flail - mine is about 6ft from my ears. Anything noise other than the hum is a mechanical issue. AGAIN IMHO.

I tried running it at 540 pto rpm and higher, ground speed was 3 mph or less(1st and 2nd gear LR)

 

[leonz]

The grass is cut, but only part of the total height. The blades during use are 2 1/2 inches from the ground, but it cuts the grass leaving it 4 to 6 tall. It cuts less and bends it over more in thick grass. The picture here is in the grass it just cut 2 days ago.


View attachment 333261

Hello justbob,

Are you sure you do not have a rear roller on it????????????????
The image of the flail mowers rotor is good enough to show you have a rear roller there.


The other issue is the belts if they are old they do not grip very well.

The mower should be run at 540 RPM with a slow grouns speed- your stating the grass is simply pushed over tells me that either the belts are wadded/shot , the engine/PTO speed is too low or the ground speed is to high.

NOW- from the photo the skids are fully raised and the mower is in the ground. The rear roller is very large in diameter as well and judging by the image you have side slicers that are too short.

The side slicers in the photo are thick not thin, are they 3 inches long in total length from the top of the knive to the bottom edge???????????

You need to reinstall the rear wheels justbob. they are there to simply prevent the corners of the mower digging into the turf as the skids are non adjustable.

 

[leonz]

The other thing that also concerns me is whether the Power Take Off rotation is right hand or left hand-if it is left hand you need a PTO reverser (which I have posted a link to on the forum here) It would explain a lot about the grass not being mowed if and only if you are operating at low ground speed and the engine speed setting is set at the 540 RPM setting or the V belts are shot.

 

[JustBob]

Hello justbob,

Are you sure you do not have a rear roller on it????????????????
The image of the flail mowers rotor is good enough to show that youy have a rear roller there.


The other issue is the belts if they are old they do not grip very well.

The mower should be run at 540 RPM with a slow grouns speed- your stating the grass is simply pushed over tells me that either the belts are wadded/shot , the engine/PTO speed is too low or the ground speed is to high.

NOW- from the photo the skids are fully raised and the mower is in the ground. The rear roller is very large in diameter as well and judging by the image you have side slicers that are too short.

The side slicers in the photo are thick not thin are they 3 inches long in total length from the top of the knive to the bottom edge???????????

You need to reinstall the rear wheels justbob. they are there to simply prevent the corners of the mower digging into the turf as the skids are non afjustable.

Read my earlier posts, it has a I installed a new rear roller and bearing kit, new belt and idler pulley. Travel speed was 3 mph and slower at minimum 540 pto rpm. Yes the knives are 3 inches total length, .093 (3/32) thick, which is thinner than any other I have seen. Maybe the previous owner installed the wrong knives?

Leonz, are you saying I should use the rear roller AND the tail wheels at the same time?

 

[leonz]

Yes Bob you need both the rear wheels and the tail wheels.

Sorry I missed the earlier posts Bob :^0

Its entirely possible they bought the wrong knives bob- these knives look exactly like the ones I have on my Mathews Lawn Genie.


EDIT: Is the flail mower level from front to back when it is on the ground bob? That would be big issue if the top link is not unthreaded enough to let it follow the ground as the skids contact the ground.

 

[IslandTractor]

The other thing that also concerns me is whether the Power Take Off rotation is right hand or left hand-if it is left hand you need a PTO reverser (which I have posted a link to on the forum here) It would explain a lot about the grass not being mowed if and only if you are operating at low ground speed and the engine speed setting is set at the 540 RPM setting or the V belts are shot.

See if the mower cuts better in reverse. If so then leonz's suspicion may be correct.

Perhaps this mower was originally set up to run in front of a tractor with front pto. That might also explain the somewhat unusual guide wheels.

 

[dieselscout80]

Are both the leading and trailing edges of those knives sharp?

If only one edge is sharp try rotating the PTO shaft by hand in the same direction that the tractor turns the PTO and watch to see if the sharp edge is doing the cutting.

 

[IslandTractor]

Are both the leading and trailing edges of those knives sharp?

If only one edge is sharp try rotating the PTO shaft by hand in the same direction that the tractor turns the PTO and watch to see if the sharp edge is doing the cutting.

Yes, both edges start out sharp. That type of knife is reversible.

 

[JustBob]

Yes Bob you need both the rear wheels and the tail wheels.

Sorry I missed the earlier posts Bob :^0

Its entirely possible they bought the wrong knives bob- these knives look exactly like the ones I have on my Mathews Lawn Genie.


EDIT: Is the flail mower level from front to back when it is on the ground bob? That would be big issue if the top link is not unthreaded enough to let it follow the ground as the skids contact the ground.

I cannot use the tail wheels, one was damaged beyond repair, that is why I purchased the roller. Yes, the mower is ran level with the roller at the highest mounting point, leaving the skids about 1.5 inches off the ground.

See if the mower cuts better in reverse. If so then leonz's suspicion may be correct.

Perhaps this mower was originally set up to run in front of a tractor with front pto. That might also explain the somewhat unusual guide wheels.

It seems to cut better going forwards, but very little difference. Which direction should the cuttershaft turn?

Are both the leading and trailing edges of those knives sharp?

If only one edge is sharp try rotating the PTO shaft by hand in the same direction that the tractor turns the PTO and watch to see if the sharp edge is doing the cutting.

The knives have only been used to cut two acres, they are still fairly sharp. A lot sharper than my lawn mower blades.

 

[Arc weld]

OK, you don't need the tail wheels and since the knives are reversible, it doesn't matter which way the rotor is spinning. Reverse rotation leaves a finer cut but you probably wouldn't notice much difference. Those are the right knives, wouldn't be surprised if they were stamped Mott. The biggest concern is that it makes a lot of noise. This is not normal. Mott's have to be run at 540 RPM and should make a turning sound almost like a big fan would, not loud and unbearable. When cutting you almost shouldn't hear it because the grass acts as a sound deaden-er. It shouldn't vibrate and should be quite smooth when running. Vibrating would indicate the rotor is unbalanced. It is highly possible that the rotor bearing(s) are shot, possibly from over or under greasing. Mott's use top of the line Sealmaster bearings and a bearing house can match them. About the only other possibility, that's extremely rare, is the rotor is bent. I only say this because way back when a stupid operator on a MF 275 with duals and with an 88" rear and both left and right hyd. Interstator wings (read heavy) got stuck and put the chain from the tandem tow truck around the rotor on the mower.:duh: After that my dad kept a spare rotor in stock.

Non Mott/Alamo belts are KNOWN to cause problems. They are specifically built for Mott/Alamo. The belt could be slipping and not allowing the rotor to turn at the proper speed. Take the belt guard off and inspect the belt, pulleys and tensioner. Maybe the tensioner bearing is binding? Leave the belt guard off to see what's happening when you're using it. Laying the grass over would indicate the rotor not turning fast enough. Could there be a problem with the gearbox? That could certainly cause a vibration and loss of speed. Last thing to check is that the PTO on the tractor is slipping or not working properly. If you can't figure it out, I'm sure Alamo would be able to offer assistance since these mowers have been around over 45 years.