I have a 11 HP Craftsman riding mower. It has a 40 inch mow deck with two blades. I have recently worked on the mowing deck - replacing some bearings and the blades. When I put everything back together, I insured the blades were 90 degrees off from each other. After I start the engine and engage the blades, they go out of sync and hit each other. I have taken everything apart more than once to insure I wasn't doing anything wrong - the same thing happens again.

Any suggestions would be appreciated.

The model number is 502 255750.

If the blades are actually hitting one another, they are too long and are the incorrect blades. Now, it is possible that the deck could be warped or bent, allowing the blades to make contact with the deck body.

I agree with MOWERMAN, timing mower blades ended years ago. Unless your machine is REAL OLD, chances are the blades are too long.

If blades measure 20 inches they are too long should only be about 19 5/8 inches

I own a john deer that isn't more than three years old and it has timing blades so I don't think you know what you're talking about. Mine hit sometimes too so I have to readjust them to be perpendicular. You can either loosen the belt and spn them or just anker one and pull the other until they are placed right.

I have a Bolens 15HP Hydro.Used it today for an hour without problems.When I restarted it the blades were catching each other.It has a toothed belt on 2 toothed pulleys on top of the deck which must have jumped a few teeth.Should be a case of simply taking belt off 1 pulley & pulling that blade around until it is 90 degrees to the other blade.I'll try this tomorrow to see if it cures the problem.

MY Craftsman II ll hp 40” cut twin blades diamond center blades
Model 502 255750 SR # 3150193

Your blades are suppose to overlap in cutting that is why they are in sink and
The belt hooking the them together is a notched belt ( like a drive chain in reverse )
And the pullies on the top of the shaft are notched to fit the belt.

SO if the pullies on the top of the shafts are not slipping and the diamond center blades are fitted on the bottom of the shaft -- it seems improbable that they should be getting out of sink...

Love my OLD first riding mower... Good Luck [email protected]
Just ordered new blades for mine.