Bent Blade - Broken motor?

skeeter1a_2010

16 years ago

Ok,

I hit a branch with my John Deere JS60H push mower. It bent the blade, not very much, but I had to go buy a new blade. When I started it up with the new blade on there was a very noticeable rattle. After the initial rattle upon startup the engine settles down but there is a lot of vibration. Could I have damaged the engine? I checked the blade, it rotates freely and everything seems solid underneath. Any thoughts would be welcome.

Thank you.

C.J.

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Comments (5)

roadbike
16 years ago
Could be a bent crankshaft, but eliminate the simple stuff first. Recheck the blade and make sure it is tight and reassembled correctly. Next look for any parts, nuts and bolts that were knocked loose and could cause a vibration or rattle.
skeeter1a_2010
Original Author
16 years ago
I finally had a chance to get another look at it. Everything appears to be tight. The blade was on correctly. I did notice at the end of the crankshaft is a blade "Adapter Fitting" (part #Gc00031). It's a big hunk of steel that is maybe a pound or so. The blade has three holes and attaches to the adapter fitting. The center hole is for the bolt to hold the blade and adapter fitting to the crankshaft. There is a hole on each side of the center hole on the blade. Those holes on the blade line up to two nubs from the adapter fitting. One of those is very visibly distorted. Inside the adapter fitting is a small metal bar that slides into a groove in the adapter fitting and the crankshaft. That "Shaft Key" also appears to have been bent a bit. I started the mower with the blade and adapter fitting off and it seems to run fine. I'm thinking that this adapter fitting took the hit and I am going to try and replace that before I have the crankshaft looked at. I went to my dealer today but I forgot it was a holiday weekend, they were closed :-(. I'll try again next week. What are your thoughts? And thank you for the reply last week.

C.J.
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baymee
16 years ago
It sounds like you have to replace the adaptor regardless. But with the blade off, any bent shaft wouldn't show up as vibration. The shaft needs a load on it for that.

Remove the spark plug wire before turning the blade. The motor could start up. It happened to me one time and I never take chances after that. Install the blade again. Make a mark on the deck that lines up with one side of the blade. Rotate halfway and see if the blade lines up very close with the first mark. If not, you could have a bent blade or a bent shaft.
roadbike
16 years ago
I assumed everything holding the bent blade was replaced. In addition to the bent adaptor I would replace the bolt as well.
skeeter1a_2010
Original Author
16 years ago
It's bent! The crankshaft is bent. I dropped it off at the shop. It's going to cost about $225.00 to fix. Here's the only good news - I inherited the machine so it's still more economical to fix this than to buy a new one. I'll have to mow with my 20 inch snapper "Lite" until the JD gets done.

Thanks for all the input guys.