lawn mower problem

[Luck e 1]

Didn't know where to put this...

Had the mower running last week...no problems. I changed the oil, air filter, and put in fresh gas.

Today I go to start it and it sounds like the blade is hitting the side of the mower...kinda a loud clanking/thumping noise...and it is shaking a little.

Then it stops running and I can't get it going again.

I turned it over to see if the blade was hitting the side of the mower...but when I turned it with my hand it wasn't close to the side.

ANy ideas?

[scsavre]

Is the sound coming from the blade and mower? or the motor itself. If you just changed the oil, It wouldnt be that knocking? Narrowing that down might give the experts the info needed.

Was the blade tight and spinning level.

[LwnmwnMan2]

If the blade was quite loose it would give you that thumping / shaking experience.

You say you can't get it running again, do you mean the engine?

[eurolarva]

If blade was not tight and it started for a bit like a second or two the imbalance might have sheared the key. If you know motors you will have to find TDC on the piston and see where it is in relation to the spark firing.

[Luck e 1]

More background:

I did have the blade sharpened and put it back on myself. The first time I used it it made the knocking noise for a moment or two, then ran like normal.

Tonight it made the same noise for a moment or two...It sounded like the blade was knocking into something...then stopped working...not abruptly...but just kinda went dead.

Now the engine won't start.

I turned it over to take a look...the bolt on the blade wasn't on the tightest...but I wouldn't say it was loose. But maybe it was loose enough.

I don't know what shearing the key means, but it doesn't sound good.

[eurolarva]

If you were able to restart it and the motor ran normal the key is not sheared. The key is for engine timing. If the flywheel key was sheared it would not start or it would backfire. My craftsman made that similar sound and I think it was oil related. It was like the bearings were dry and rusted. When the engine went dead can you pull the starter chord or is that locked up as well?

[Luck e 1]

After I cut my lawn for the first time last week I was able to restart it last night...but it only ran for 5 seconds before it died. And for those 5 seconds it was knocking pretty bad.

When I pull the chord there is tension...but it won't fire up.

[BoxMN]

Sounds like what happened when my brother hit the granite brick when we were kids Bent shaft, new mower needed. Hope that is not your case.

[lawdog]

What kind of mower is it? I had a lawnboy where the muffler baffles used to just rot away and fall apart and it would make a Godawful noise rattling around in there. A little more info may help...

[LwnmwnMan2]

Yes, a little more info.

A riding mower? Or push?

Brand?

You can start it, with a key? Or pull start?

[Luck e 1]

I took it to a guy who pulled it apart and found a sheered fly wheel key as previously mentioned.

He is going to fix it for me tomorrow.

Thanks for the help guys...

[cygnus]

Have you ever hit anything with the mower? The knocking could be coming from blade adapter. Many of the blade adapters have their own keyway built into them that slides over the crankshaft. Take the blade off and see if the keyway inside of the blade adpater is worn or it might be completley sheared off. This can cause the blade adapter to rattle (knock) when the blade is spinning. Does the machine vibrate excessively when it runs? And, if you did hit something you may have partially sheared the flywheel key. Enough to make it hard to start and run bad. There is no timing procedure to replace the flywheel key. Remove the flywheel, replace the key and retorque is all that is necessary.

[Luck e 1]

The guy fixed the fly wheel key and now it runs like a champ.

Thanks though.