Rotary mower stalling

[Firefighter912]

Rotary mower keeps stalling on me. I have it up to the 540 mark and it starts bogging down in the grass. I have mowed with it before, but now it seems like it doesn't want to do nothing but stall out.

Basically, the pto just stops until I lift up on the mower deck. I don't have a slip clutch pto shaft on it.

The other mower I did use would cut with no problem through the grass

I am about fed up with it. The grass isn't insanely thick either.

What could be the issue? Guy I bought it from supposedly put a new gear box, stump jumper, and blades on it.

 

[Firefighter912]

Here are the picsit

 

[leonz]

View attachment 562356View attachment 562357


Here are the picsit

It looks like you have a slip clutch on the end of the PTO drive shaft at the gearbox.

 

[jeff9366]

1) Are the blades sharp?


2) Mower should NOT be level. If level, grass is retained within.

Front of mower should be 1" to 2" LOWER than the REAR, so only the front cuts and at the rear the blades exhaust clippings.


3) A deck with less height does not mow longer grass as well a a deck with greater height.

 

[RjCorazza]

Without a slip clutch shouldn’t the tractor stall, or shear pins?

 

[jeff9366]

A slip clutch has to be adjusted properly, annually, not too tight and not too loose. If too tight, it will not slip. Mower will bog.

If too hard a shear bolt is installed, mower will bog before pin shears.

 

[RjCorazza]

My point was that since the op doesn’t have a slip clutch, and says the mower is stalling to the point of stopping the pto, shouldn’t the tractor stall?

 

[ericm979]

Sounds like the PTO clutch (independent PTO) or tractor clutch (live PTO) is slipping. If it's an independent PTO it could be worn or since the pressure comes from the hydraulics, the fluid could be low or filter blocked. With the live pto the tractor clutch mechanism could need adjusting or the clutch is worn out and slipping.

 

[Oldoak]

Sounds like the PTO clutch (independent PTO) or tractor clutch (live PTO) is slipping. If it's an independent PTO it could be worn or since the pressure comes from the hydraulics, the fluid could be low or filter blocked. With the live pto the tractor clutch mechanism could need adjusting or the clutch is worn out and slipping.

:thumbsup:

I don't have a slip clutch pto shaft on it.

People just confuse the issue talking about a slip clutch on the PTO drive shaft which isn't relevant in the case of the original poster. :confused3:

 

[ratpie]

flip it over and make sure that the guy ya bought it from didn't put new blades on it. mine bogs down a bit when blades are needing some lovin. also check fluid levels and grease fittings. if that don't fix it move up to the tractor and figure out why the torque is dropping.

 

[N2DFire]

Basically, the pto just stops until I lift up on the mower deck.

If you mean, as I am interpreting it, that everything from the PTO output on the rear of the tractor and the entire PTO shaft on the RC (basically everything in the pictures you attached) stops spinning until you lift the cutter back up - then your issue is in the tractor and not the cutter and I would refer you back to what ericm979 said.

If the PTO output on the tractor & the RC PTO shaft is still spinning but the cutter head is not turning, then you have either sheared a pin between the shaft & the gearbox or the gearbox is trashed. Since you also state (and show) that you do not have a slip clutch, then a shear pin is the most likely culprit in this scenario as that is how the RC is designed. The pin shears off before something more expensive breaks since there is no clutch.

 

[ericm979]

One other thing that can affect hydraulic pressure (downstream) would be if you have a hydraulic valve deadheadding and the relief is open.

 

[Firefighter912]

I think I do have it too leveled.

I am probably going to take the slip clutch off the older mower and put it on this mower and see how it does.

I have an independent pto.

 

[MESSMAKER]

It looks like you have an input shaft on the gearbox has splines. That is for use with a slip clutch. You say you don't have one and neither do I but I don't see how a shear pin will work on a splined shaft. You may not have a solid connection. from pto to gearbox. Does your shaft slow when the cutter bogs?

 

[Fallon]

It looks like you have an input shaft on the gearbox has splines. That is for use with a slip clutch. You say you don't have one and neither do I but I don't see how a shear pin will work on a splined shaft. You may not have a solid connection. from pto to gearbox. Does your shaft slow when the cutter bogs?

My flail had splines on it. Flails typically rely on the belts slipping for protection. The replacement shaft I ended up with has a sheer pin inline with the shaft on one side despite not needing protection. Part of the shaft itself slips on itself if the pin pops. A bit of an uncommon design, but gets protection on a splined input.

Braber Equipment General-Purpose PTO Shaft Assembly - 36in. Collapsed Length, Model# 69.885.005 Amazon.com: Braber Equipment General-Purpose PTO Shaft Assembly - 36in. Collapsed Length, Model# 69.885.5: Automotive

 

[ruffdog]

When the mower stalls, does the PTO shaft (inside the safety shield) also stall? If it does, the clutch inside the tractor is slipping.

If the PTO shaft keeps running properly when the mower stalls, check the connection of the gearbox output shaft to the stump jumper/blades. Is the nut tight? Splines stripped? Key sheared?

 

[Firefighter912]

Here is a video of it

Rotary mower stalling - YouTube

I did install my old slip clutch pto shaft.

I may need to adjust mower more, but the rear wheel also needs to be fixed and could be my issue as well as my top link doesn't have the other piece if metal as well.


The gear box is a 40 hp with a 1:1.47 gear ratio. Don't know if that could be an issue.

I was debating about getting the old gear box off my junk mower.

What do yall think?

Here are more photos

 

[LouNY]

I just watched your video, it was hard to say but it appeared that your pto was slowing down,
my suspicion would be as has been mentioned that your tractors pto clutch is slipping,
if so it's not your bush hog it's your tractor.
The easiest way to check would be to find a shop with a pto dyno and load your tractor with it.

 

[ericm979]

PTO inside the tractor is slipping. See my earlier post. It's not the mower or the external shaft. Do you have an independent PTO or a live PTO?

 

[ruffdog]

It's not your mower, it's your tractor. Either your clutch is slipping because it's shot or because the clutch peddle/shaft is rusted so it's not releasing all the way. Sort of like keeping your foot partially on the peddle all the time.