MMM Clunk and Black Smoke

kday64 · May 8, 2011

All,

Yesterday I installed my 54" MMM on my BX2360 for the first time. I am a little concerned though. When I engage my Mid-PTO I hear a clunk, the tractor hood shakes a little bit, and then a puff of black smoke comes out of the muffler. This does not happen when my rear PTO.

The sound similiar to the sound my family's old ford would make if I was light on the clutch the when engaging PTO implements. If I was too light I would also shear a shear pim.

Before starting any PTO I lower the engine RPM to 1300 to minimize the shock put on the PTO and the implements just as the users manual says to.

I know on the rear PTO there is a slow ramp up when engaging a PTO. ie does not start at 540 RPM instantly. Does the Mid-PTP have the same? Is this something I should be calling the dealer about.

~Kevin

thavil · May 8, 2011

In my opinion, you are engaging the MMM with not enough RPM. I have experienced the black smoke when I did the same thing when I first got my BX24. I now always engage the PTO at 1600-1700 RPM's and never get any smoke.

The mid PTO has a slight ramp up while moving the level into position.

CHDinCT · May 8, 2011

Agree with thavil. 1,300 RPM is too low in my experience (I think mine idles above 1300 anyway). The lack of power at 1300 RPM will cause the black smoke but I'm not sure what the clunk is you're hearing. Just make sure the PTO shaft is locked securely onto the mid PTO shaft. If it isn't and comes loose at speed, it can be an ugly scene (and expensive repair depending on what the rotating shaft hits).

kuboman · May 8, 2011

Sounds quite normal. I have my idle set slow enough that it will just engage the pto without stalling. A little smoke is no big deal. The lower the engagement speed the easier on the the drive line, clutches etc.:thumbsup:

sw03 · May 8, 2011

I always engage my 60" deck at the lowest RPM on my BX24; you want that based on the manual. Did the same deal on my old BX22. CLunk, you are on your own....

Evil the Weasel · May 8, 2011

As others have stated, it's best to engage the mower at lowest RPM and then bump it up to operating speed.

keyman1808 · May 8, 2011

The book on my BX24 says to engage at half RPM. Low idle is 1100 and WOT is 3200 so I engage at about 1800. Never had any smoke or clunk.

kday64 · May 8, 2011

So I did a little trial and error.

1) the higher RPM stopped the black smoke and stalling sounds.

2) the higher RPM created less hydraulic shock and the hood was bouncing / slamming

My wife who was standing next to the tractor was kind to point out that the noise was from the hood not the pto.

Thanks all!

~Kevin

thavil · May 9, 2011

kday64 said:
So I did a little trial and error.

1) the higher RPM stopped the black smoke and stalling sounds.

2) the higher RPM created less hydraulic shock and the hood was bouncing / slamming

My wife who was standing next to the tractor was kind to point out that the noise was from the hood not the pto.

Thanks all!

~Kevin

Good to hear that the higher RPM helped out. What I did for my plastic hood on my BX24 was to put some foam window sealant strips around the inside edge of the hood where the hood touches over top of the dash. This possibly would work on your metal hood also.

kevinj · May 9, 2011

kday64 said:
So I did a little trial and error.

1) the higher RPM stopped the black smoke and stalling sounds.

2) the higher RPM created less hydraulic shock and the hood was bouncing / slamming

My wife who was standing next to the tractor was kind to point out that the noise was from the hood not the pto.

Thanks all!

~Kevin