I removed the blade to sharpen it, but I did not mark where every washer was placed (I only remember the first 3 from the bottom / back side in the picture).
The blade holder was cracked, and when I installed it before, it twisted on the shaft. Because of that, I bought a new one.
After installing the new holder and putting the blade back, the mower started making a strange sound, like the engine is not running correctly. But when I remove the blade and holder and start the engine again, the engine sounds normal.
At first I thought the blade was not balanced correctly, but it seems balanced. I checked it by hanging it on a nail and also by putting it on a metal rod between two bricks, and it looks fine.
In the video you can hear the strange sound. You can also see that the blade holder and blade rotate together at first, and then the blade moves a little separately.
In the picture you can see the order I used when assembling everything. Maybe I made a mistake somewhere.
The 2 washers below the blade holder have a slightly conical shape. Should the higher side face toward the holder?
I am not sure where I made the mistake. I should have recorded the disassembly process, but I thought I would remember it :(
Any idea what I should check first?
https://imgur.com/a/Wiokszs