New X749 with 54C deck has terrible cut quality

[BBO]

Have you put the mower on a flat concrete slab and checked the side to side level? Tires exactly the same pressure?

My 445 with the 60" deck is the most sensitive I have ever worked on related to air pressure.
It seems 1 lb of pressure variance will screw the thing totally up.
The wider the deck and the slimmer the wheel base the more sensitive this is.

The fatter you are and the more you lean you might skew the cut.:shocked:

And, you need a low pressure gauge to check this, like used on ATV tires.
OT Low Pressure Air Gauge

It's interesting that you have trouble with the X758.
But I know one guy that bought a Kubota similar to this size mower and is having the same trouble as you.
He gave $12000 for the mower and sold it after 15 hours mowing for $9000

 

[eagle107]

Man that is absolutely terrible. My Ferris will scalp a little on the low side like that when mowing on a slope, but never on flat ground. I have some pretty good slopes and no matter which direction I go, I either get the ledge cut like in the photo if going parallel with the slope or scalp the top of the hill when the mower breaks over the top and leave it a bit long when leaving the slope at the bottom. If I raise it to 3" height, it isn't as noticeable but its still there. Yours seems to be doing it all the time. Have you put the mower on a flat concrete slab and checked the side to side level? Tires exactly the same pressure?

I have adjusted the mower multiple times, and then the service manager from the JD dealership took my X748 two weeks ago, check/adjusted the tire pressure and adjusted the mower twice to make sure everything is correct, but the deck still does not cut right. I really believe at this point it is a design flaw with the larger mowers. The mowing deck is just rigid on the X748; there is no flexibility in the deck to float. So when the tractor hits a depression or rides on an angle, the deck staying fixed just following the angle of the tractor and trends to dig in, which you can see from the photos. I mow at 2.5" and if I raise the deck to 3" it is a little better, but not much. Now the Wood PRD8400 (84") mower is set to 3" and when I hit bumps or cut embankments, the 3pt hitch pivots allowing the mower to float and leaves a great cut all the time. The 60" 7-iron deck will cut fine on very flat surfaces, but once you hit minor or major bumps in the lawn, the cut quality goes downhill fast as the photos show. I guess I will have to write to JD to see if they know a fix for this or if anyone has a trick to fix this, I am all ears. Thanks!

 

[jenkinsph]

I haven't had any issues with my 749 like that but I would be pissed and wan't a fix for that. I did buy the mulch plug and blades and tried them out when it was new, didn't care for the cut I got. Been running the standard blades since then and occasionally using the MC519 cart when I need to pick up debris. Generally pin the wheels in the sixth hole counting from the top of the shafts. Check the tire pressure with a 0-20lb guage and set for 9psi. I mow my Fescue at 3 to 3 1/2 inches most of the year so that might help but it still comes out even all the time.

 

[eagle107]

I haven't had any issues with my 749 like that but I would be pissed and wan't a fix for that. I did buy the mulch plug and blades and tried them out when it was new, didn't care for the cut I got. Been running the standard blades since then and occasionally using the MC519 cart when I need to pick up debris. Generally pin the wheels in the sixth hole counting from the top of the shafts. Check the tire pressure with a 0-20lb guage and set for 9psi. I mow my Fescue at 3 to 3 1/2 inches most of the year so that might help but it still comes out even all the time.

Yes, the tire pressure was double checked at the dealership and the mechanics made sure the front tires were set to 7psi and the rear tires were set to 10psi. I sent an email off to my dealership's service manager with same photos and the service manager is really upset that the 7-iron deck is cutting like this. He called me and stated that the deck is a commercial deck and should float like the Woods and Scag decks. He is going to have tractor picked up soon, but he want to have his tech submit a D-tech ticket to JD first and work with JD to figure out why this might be happening. I am glad I have such a great JD dealership to work with. Hopefully, they can work with JD to figure something out.

 

[CinderSchnauzer]

I think reading this thread saved me about $13K - $15K.

Was thinking of a JD X7xxDiesel to upgrade from my 2006 Craftsman. Since this was a "want" more than a need and the Craftsman is still working, as well as it always did, doesn't seem worth the $$$$ to get no better or perhaps even worse cut quality.

 

[murphy1244]

Yes, the tire pressure was double checked at the dealership and the mechanics made sure the front tires were set to 7psi and the rear tires were set to 10psi. I sent an email off to my dealership's service manager with same photos and the service manager is really upset that the 7-iron deck is cutting like this. He called me and stated that the deck is a commercial deck and should float like the Woods and Scag decks. He is going to have tractor picked up soon, but he want to have his tech submit a D-tech ticket to JD first and work with JD to figure out why this might be happening. I am glad I have such a great JD dealership to work with. Hopefully, they can work with JD to figure something out.

Sounds like you have a Excellent Dealer. That is sooo important.

 

[Jimh4662]

The x758 is a Premium top notch tractor. That's the trouble. JDs flag Ship lawn mower. Apparently designed from ground up, using input from users dislikes or wants. 54HC Deck and mower combination cuts terrible

 

[murphy1244]

The x758 is a Premium top notch tractor. That's the trouble. JDs flag Ship lawn mower. Apparently designed from ground up, using input from users dislikes or wants. 54HC Deck and mower combination cuts terrible View attachment 337291

 

[Gator6x4]

I would suggest the following. (1) Raise the tire pressure to 12 PSI for front and rear tires. (2) obtain a blade height adjustment tool from JD. The plastic device cost about eight dollars. This will allow you to accurately adjust the front to rear and side to side deck height. (3) park the mower on a flat level service, lower the deck then take a lift assistant (stick) and see if you can raise each side of the deck. If the deck will not move upwards, something is installed wrong which is not allowing the deck to float.

Comment: From the photos posted it appears the deck is lower on one side than the other and the front to rear adjustment is also off.

 

[BBO]

I would suggest the following. (1) Raise the tire pressure to 12 PSI for front and rear tires.

I kinda agree with slightly higher pressure that will keep them for running lower on a sideways slope.
That mower seems too heavy for 7psi.
In some cases I find it necessary to run more air in one front tire to level my old deck up.

My neighbor has a sloping yard like the one in this photo above and I mowed it last week.
Even with my deck it was butchered up similar to this.
They mow it up and down the hill like you did. I mowed all of it in a CCW circle.