I have a John Deere GX345 that leaves a skip between the blades. The skip is between the center blade on both sides. I thought the blades were wore out. So I replace with new blades. Still have a skip. I have been buying blades from the same place and length of blades are right. Do the blades need to be timed or shouldn't it matter?

No expert but do the blade tips appear level and nearly touching when you line them up?

How much of a "skip" are we talking about?

If blades are correct I would think something was off (worn/bent spindle comes to mind) that was causing

Also try slowing down, used to have similar issues when I was young and mowing on my grandad's rider. Try and go too fast and strip of grass between blades.

Look up blade part # for deck model rather than tractor model.

About a inch per side.If spindle was bent or worn I would there there would be a vibration somewhere. I have had this mower for over 15 yrs. It started last fall and kind of forgot about till spring. Maybe I will go to the John Deere dealership and buy another set of blades.

I had the same problem. Bought new blades and still the same. Took them off and really sharpened them and that fixed it.

I would check deck belt,, pulleys and pto clutch to make sure your not getting slippage. Them blades wii slide over the grass so to speak if belt is semi slipping.

Maybe the blades are for the wrong size deck. Sounds like you have a 54in deck with 48in blades. I may have learned this the hard way once
54 in = 18.693 IN blades
48in = 17.047 IN