Hi,

I have a Murray Model 40542C 40" riding lawn mower. I recently took the blades off to have them sharpened, and since putting them back on, there is a lot of vibration (some times, not always) when I engage the blades, and some times it even stalls the engine. It runs fine without the blades engaged, in all gears, and sometimes the blades will engage. Once engaged, there are again times where it seems fine, then some times there is a lot of vibration from the cutting deck, and it stalls again.

When pulling the blades off, one was very difficult and I was forced to use a pipe wrench behind the jackshaft pulley to keep it from spinning in order to loosen the nut holding the blade. Is there a chance the pulley or jackshaft is now slightly bent?

I should also add, there are two different blade widths involved here, which I am told means that at least one of them is the incorrect blade, as they are supposed to be the same. It did work fine prior to removing them, and I have tried swapping them to see if there is a weight balance issue, but I have the same symptoms regardless.

Two more quick additions...

When it does stall, I notice a lot of shaking from the idler pulley, although there are times it engages fine and there is no shaking from the idler pulley. I also did notice a lot more noise from the blades when engaged than was there before. Best way I can describe it is like a 'chatter'. Not a real bad metal to metal sound or anything real obvious, just nosier.

I'm stumped.