Adjusting the MMM

skipperbrown · May 17, 2002

I have a BX2200 w/ the 60" mmm. My deck cuts one side a bit lower than the other so last nite I decided to pull the deck off, sharpen the blades, grease, and generally clean it up, figger out how it works, and get the thing properly adjusted.

The directions say to first adjust the front linkage for a parallel cut so the blades are parallel to the ground front and rear. I did this procedure until the blades were parallel to the ground. No sweat although a bit tricky measuring the blade on the side w/o the exhaust chute. I spent about 30 min. micro adjusting until the port and starboard blades were perfectly level front and aft.

Next it says to adjust the lift arms linkage so the link arms come within 3/32" of the link stop. I think this procedure insures you can lock the deck w/ the height adj knob. This involves adjusting the double nuts at the back of the tractor. My linkage required about a 1/2" up adjustment until I had the 3/32" clearance. OK, all that should be left is adjusting the side to side height, right? Wrong.

I dropped the deck to my 3" cutting level and my first parallel adj (30 min) was now way out of wack by 3/8" front to rear and the side to side is now off by over an inch unless I flex the deck and compress the springs (The directions say this is the next adjustment). And if I rock the deck, it doesn't always settle in the same position. This must be a difference in spring compression.

Also, another complication: I have the height adj knob set at 3", but the starboard (right side) blade was only 2" from the ground. After the initial parallel adjustment, it said 3" but the blade was actually 2 5/8" high which is close enough for gov't work. However, a full inch seems like excessive error. It was now 9:30pm and being frustrated I quit for the nite.

Any advice on how to get the deck back to flat. Are the directions out of order? Are they correct? It seems it would be best to adjust the back of the deck first and then the front linkage. Suggestions or comments?

thanks,
mark

TresCrows · May 17, 2002

You can use the manual only as a guide. It is mostly BS. I sat down and studied the manual and then looked at my decks and then after thought about what it is I wanted I began adjusting to get what I wanted. It is kinda intuitive and kinda trial and error. The good thing is that it may take several tries but once done it is done forever--I hope. On the BX since the deck is suspended it will require that you average out your side to side adjustments by manually leveling the deck by hand as you adjust. Try to adjust the levelling spring that it is neutral when the deck is level--what I am saying is that there is enough friction that it will not return to level on it's own but of course as the tractor bounces along while in motion the spring does do it's work and maintain an average level. Also the suspension rods and the front attach bracket all play a roll in keeping the deck level, and further--do not even think that just because the knob says--3 --or 2--or 2.5 etc that the deck is going to cut exactly that. It may be a little this way or that and you will just have to by use find the setting that gives you what you want. Does it really matter that you have to--for example--use the 2.5 position to get a "real" 3 inches or whatever? You might be being to critical on your adjustments or what you are trying to achieve. J

Anonymous Poster · May 17, 2002

What is the height adjustment range for this deck? I.E., what is the shortest it can cut / what is the longest?

MReeter · May 18, 2002

Skip,first of all/check the air pressure in the tires,making sure all are equal. The 3/8" difference in the front edge of deck compared to the rear edge is supposed to be there.

The front edge should be 1/4"-3/8" higher than the rear.This allows more volume of grass to enter the deck,plus this keeps the blades from "stripping" your grass.The blades on any 2-3 blade deck are off-set,if you have the deck perfectly level,you see the off-set in the grass.

As for the side to side adjustment,I can't help you out much there.I would adjust the deck as well as I could with the linkage,regardless of what it looks like on the threaded adjusters.

On our G1900,when the deck is fully raised,one side is higher than the other.When lowered to mowing position its levels right out.I've noticed the deck on the BX does a little bit of the same,just not quit as noticeable...

skipperbrown · May 20, 2002

Thanks for the advice Trescrow and Mreeter. You were both right on.

First, I made sure the tire pressures were accurate. Second, I adjusted the starboard side for correct lift height. Third, I adjusted the port side w/ the deck lowered so the starboard and port side were level after flexing the deck as Trescrow recommended. As Mreeter pointed out, at full lift the port side is about 1/2" lower than the starboard side. No big deal. Finally, I adjusted the front links. Now at the 3" position, she cuts at 2 3/8" which is right where I want to be. The manual sez to adjust the front linkage first, but that's not right.

Now she mows like dream!

thanks,
mark

Hoosier_Daddy · May 20, 2002

Mine MMM cuts fine but I checked level anyway when I got it. Seemed to be measuring OK so I left it alone. Then when I took it off to play with the FEL back in the woods, I noticed the front linkage nuts were loose. One was backed off quite a bit.... I wish these Turkeys would tighten things up when they deliver them..... Makes you wonder what might fall off without any notice.

I don't use the theory I had with my first junker car. If something fell off going down the road we would just say "if it runs with out it, I guess we didn't need it"....... Tom