312-8 w/42" deck bogging down

[Craig-906 28]

I have a 312-8 w/42" deck that really only allows me to mow in first gear. The lawn isn't overgrown. When I try to mow in 2nd gear the deck slows right down to where you can see the spindles slow down and hear it, while the engine doesn't bog. I have replaced the belts on the deck, and the pto to power the deck (its on the inside pully), drive belt will be next to be replaced.

 

The attach-o-matic is real tight, so its not slipping there.

 

Is there an adjustment on the deck I do not see?

 

Blades are sharpened.

 

I'm at a loss, seem to point to either poor tension on the deck itself, or wrong brand/type of belts (tractor supply v belts (husky).

 

What am I missing?

[Darb1964 1,115]

Check your mule drive for worn out parts and that the spacers are there.

[Handy Don 14,056]

Yep, there is too much friction in the mechanism that is turning the blades or not enough friction in what is driving it.

Did it ever mow correctly? If so, what has changed?

 

If you are not seeing belt(s) slippage, there is no need to further tighten belts--in fact, you may want to back off until just a bit tighter than when it slips.

You seem pretty sure the belt isn't slipping on the PTO and you don't mention that the engine is bogging down. I'd also look to see is the PTO clutch itself slipping? (A good sign of this is that the PTO pulley "bell" will get hot.)

Edited May 11, 2022 by Handy Don

[Craig-906 28]

3 hours ago, Darb1964 said:

Check your mule drive for worn out parts and that the spacers are there.

Seems ok?

 

[Craig-906 28]

1 hour ago, Handy Don said:

Yep, there is too much friction in the mechanism that is turning the blades or not enough friction in what is driving it.

Did it ever mow correctly? If so, what has changed?

 

If you are not seeing belt(s) slippage, there is no need to further tighten belts--in fact, you may want to back off until just a bit tighter than when it slips.

You seem pretty sure the belt isn't slipping on the PTO and you don't mention that the engine is bogging down. I'd also look to see is the PTO clutch itself slipping? (A good sign of this is that the PTO pulley "bell" will get hot.)

Not entirely sure, I changed the belts in the fall when I got it as they were checking. I’ll check the bell tonight when I get home and mow.

[8ntruck 7,829]

Check the 'C' clip that is on the outside of the PTO bell on the stub shaft that the PTO hoop pushes on.  If the 'C' clip is not in the groove on the stub shaft, force is not being applied to the PTO clutch.

 

Good luck.

[Craig-906 28]

6 hours ago, 8ntruck said:

Check the 'C' clip that is on the outside of the PTO bell on the stub shaft that the PTO hoop pushes on.  If the 'C' clip is not in the groove on the stub shaft, force is not being applied to the PTO clutch.

 

Good luck.

Which part are you referring to?

[Craig-906 28]

9 hours ago, Handy Don said:

I'd also look to see is the PTO clutch itself slipping? (A good sign of this is that the PTO pulley "bell" will get hot.)

Its pretty warm, I don't think its hot considering the location to engine and muffler. I can touch it.

[8ntruck 7,829]

34 or 35.  There is a snap ring on both sides of #36 ball bearing.  If the external one is loose, broken, or missing, #31 won't be pushing on the pulley to engage the clutch.

[Handy Don 14,056]

Two trains of thought going at the same time.

 

@8ntruck is asking you to make sure that when you engage the PTO, the pulley/bell/clutch are all pushing toward the engine with the proper force and, therefore, driving the PTO belt properly.

 

That is what my suggestion for heat was about as well. If the bell is turning but not with sufficient force, it will slip (and get hot from the friction) where it is being pressed against the engine and not deliver power to the deck.

 

The most common causes of insufficient tension are a poorly adjusted rod (#31), trunnion (#13 and #14), or a failed snap ring (#34 or #35).

 

Is the PTO turning at the same speed as the engine, even when the deck is bogging down?

[8ntruck 7,829]

I just realized that I did not give the back story on my advice to check that 'C' clip.  I guess it was last spring and the 42" RD deck was bogging down in taller grass - just like @Craig-906 is describing.

 

The treunion (#14 in the diagram) on the PTO rod was already threaded all the way onto the adjustment threads, leading me to think the clutch lining was worn out.  While installing the new clutch lining, I discovered the outside 'C' clip out of place on the stub shaft.  Installing a new 'C' clip restored proper PTO operation, without installing the new clutch lining.

[Darb1964 1,115]

On 5/11/2022 at 12:37 PM, Craig-906 said:

Seems ok?

 

Hard to tell but it does look like it may be rubbing on the bottom guide pulley. It's possible to over tighten the nut especially if the spacer is missing. Many years ago I had that problem, heats up and expands as you cut. Took me a while to figure it out.

[Craig-906 28]

So I finally had time to look at this and take it apart. Worn PTO brake.

 

Clutch housing, seems all parts are present. Is the clutch plate worn out?

[8ntruck 7,829]

The clutch lining looks OK.  What is it, about 1/8" thick?  Is the clutch lining plate flat?

 

Is the clutch surface of the PTO bell flat?   This can be checked with a straight edge.

 

On the stub shaft in the palm of your hand in the pictures have a C clips on both sides of the bearing it goes through seated properly in their grooves?

 

Any slop in the linkage  between the PTO and the PTO clutch lever?

[Handy Don 14,056]

7 hours ago, Craig-906 said:

 

Clutch housing, seems all parts are present. Is the clutch plate worn out?

The engine-side disk is far from worn out, there is plenty of material.

 

From its wear pattern, however, it seems much more like it is meshing poorly with the PTO side disk in only a few places--less than half of its surface. Clearly, it is not able to transmit full force to the deck this way.

As noted above, are both of these plates flat? It looks to me like the engine-side plate is not flat.

Is the PTO engagement linkage really putting enough pressure on the clutch? See above suggestions.

 

I would also make sure to sand off that engine side disk to remove any contamination or crud that is on the face, especially in the places that look worn.

 

[8ntruck 7,829]

A couple more thoughts - are the four bolts holding the clutch plate all tight?  Pull the clutch plate off and check to make sure the mounting surface is clean?

[cschannuth 3,817]

I had a like new, very low hour 314 with a 42 inch deck and it was all that I could do to pull it in second gear and the only way I could get it to provide a nice cut was to cut in first gear. I would think a 12 hp tractor would struggle even more. The C-161 pictured in my avatar mowed with a 42 inch deck in third gear and never breathed hard so I assumed that a much newer 314 would handle it in second gear easily. That was not the case. I do have a very thick yard, however. 

[Craig-906 28]

9 hours ago, 8ntruck said:

The clutch lining looks OK.  What is it, about 1/8" thick?  Is the clutch lining plate flat?

 

Is the clutch surface of the PTO bell flat?   This can be checked with a straight edge.

 

On the stub shaft in the palm of your hand in the pictures have a C clips on both sides of the bearing it goes through seated properly in their grooves?

 

Any slop in the linkage  between the PTO and the PTO clutch lever?

A good 1/8th on it. I'll check both for even plane.

 

Both c clips are seated and not broken.

[Craig-906 28]

8 hours ago, Handy Don said:

As noted above, are both of these plates flat? It looks to me like the engine-side plate is not flat.

Is the PTO engagement linkage really putting enough pressure on the clutch? See above suggestions.

 

I would also make sure to sand off that engine side disk to remove any contamination or crud that is on the face, especially in the places that look worn.

 

Going to check plane on both sides.

 

The trunnion is about as tight as I can make it without bending the linkage when engaged.

 

I'll sane the engine side disk and see how it goes.

[Craig-906 28]

6 hours ago, 8ntruck said:

A couple more thoughts - are the four bolts holding the clutch plate all tight?  Pull the clutch plate off and check to make sure the mounting surface is clean?

I will check these when I check the plane.

[953 nut 59,908]

4 minutes ago, cschannuth said:

I do have a very thick yard, however.

To me that is the tell all statement. Much of my yard is heavily shaded and can be mowed in third gear with my 42" rear discharge deck on a 310-8. The portions of the yard that get a lot of sunshine I need to go down a gear and if I procrastinate and let the grass get too tall I'm down to first gear. A couple of years back I put the same deck on the 418-C and had to use about the same speeds in the same conditions, just used more gas. If I've been away for a couple weeks I tend to half lap the previous cut to reduce the amount of  bogging down.

9 hours ago, Handy Don said:

From its wear pattern, however, it seems much more like it is meshing poorly with the PTO side disk in only a few places--less than half of its surface. Clearly, it is not able to transmit full force to the deck this way.

Yes, but there are no signs of overheating from slipping clutch. As thin as these backing plates are I'd bet there are a lot out there that aren't flat that are doing just fine.

[peter lena 9,252]

@Craig-906  dare I  ask , how easily does that deck spin by itself , by hand ? you obviousely have a combination of drag areas / issues . regularly checking my stuff / anything , always look and verify its easy , solid function . with deck off , upside down , how easily or difficult do those blades spin as a unit ? if your spindle bearings are in a failure state , also related , same size mule  drive bearings rough or grinding . you are probably cooking that clutch and related drive points , with other resistance areas . to me , your set up needs an experienced eye , from a near by fellow horse user , to quickly zero in on the issues. if those decks are properly lubricated and serviced , they spin , by hand with ease . making the belt drive work with ease , hopefully there is a local fellow horse  owner , for a look see , to your problem , pete 

 

[peter lena 9,252]

@Craig-906  was just noticing , is your mule belt drive adjustment , way out on the end of the adjustment knob / threaded rod ? thats also a weak drive belt area . belt tension should be close to tech a matic  starting pull point. if your belt is also fighting an improper extended drive angle , that will degrade its drive function . my  mule drives all make up , at the very start of belt pull , letting the front of the drive be square to it s mount point . hope you get some help , pete  

[Lee1977 7,194]

Have you checked the deck belt?  Could be worn or the belt  could be not working because of worn bushings or trash build up on the tension bar. There is also a spring thar keeps the belt tight. I did replace the spring on my 48" deck after 30 some years.

[Craig-906 28]

17 minutes ago, Lee1977 said:

Have you checked the deck belt?  Could be worn or the belt  could be not working because of worn bushings or trash build up on the tension bar. There is also a spring thar keeps the belt tight. I did replace the spring on my 48" deck after 30 some years.

New belt, spinning freely, spindles are free and no play.