i have a 42" riding lawn mower i just replaced the blades on, but?

Question

i still miss a small strip of grass down the middle of every pass! why?

p.s. i`m sure the blades are the right size!

also, it`s a 42" craftsman command with a 15 horse motor and has the star design in the center of each blade.

Answer 1

Make sure you didnt put the blades on upside down.

Make sure the mower deck is level, left to right and front to back, when lowered to mow. That is the most likely culprit. With the mower on pavement and turned off, lower the deck to the mowing position. Measure the height of each blade tip, from the ground to the blade. Do this with the blades rotated front to back and side to side. The blades must be level, not the lip of the deck.

If there is a belt on the deck, it probably has a tensioner, is the belt running true and tight ? Same goes for your PTO belt from the tractor to the deck if so configured.

Double check that they are the correct length blades.

When inspecting the blades, pulleys, tensioner pulley, be wary of a bearing that is shot and causing a pulley or blade to not track true.

Make sure all belts are routed correctly. That sounds silly, but I have seen lots of belts put on wrong. OK, I admit, I have even done it. ;) When on correctly, the belt should wrap nearly 180 degrees around the blade pulleys in most setups.

When mowing, blade speed is your friend, get them spinning up fast and you mow better, mow frequently enough so you are not removing more than 1/3rd of the grass length, usually less than one inch of removal for most yards.

Did you clean out the mower deck when changing the blades ?

You have probably thought of most of these things already, but thats my two cents, good luck.

John

Answer 2

John definitely covered all the bases, but I just want to point out a simple possibility. It may be that you are asking the blades to cut too much. If your grass is really tall (or the deck is set too low), the mower will leave what we like to call "skippers." The skippers happen at either end of the blades (because grass that is cut towards the center of the blades rotation is actually cut twice, once in the front of it's travel, and again at the back). In your case (I'm betting the 42" has only 2 blades), there will be the potential for three rows of skippers, but you'll only see the one in the middle. The one on the discharge side won't actually show up because this is where you are overlapping your previous cut. The one on the other side you won't see because it is along the edge of the uncut grass. That leaves the one right down the middle.

Assuming the blades are the right size, installed and aligned correctly and everything else is to spec, you might just try raising your cut height if the grass is tall (cut it twice, once high and then at the height you want) and slow down your ground travel speed (keeping the throttle up).

Answer 3

Make sure the underneath of the deck has all the old grass cleaned out and check the air pressure in your tires to make sure they are the same. Also grab your blades while on the mower (NOT RUNNING of coarse)and see if there is any play up and down on the blades. You could also have spindle bearings going out.

Answer 4

simple, at the center of the blade, there is no cutting edge, so a tad piece of grass remains un cut with will be cut on the next pass unless you are too far away and miss it.

Answer 5

ensure the blades are on the housing in the correct place if there is a slot and they are not in the correct position the baldes will be out of sync each blade should be on a pimple or slot what kind of machine is it?

Answer 6

I have to believe that the blades are too short.

Answer 7

Check blades for dull , end broken or bent.