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jim · 20-05-2010, 06:24 PM posted to alt.home.lawn.garden

wrote:

On May 18, 11:05 am, jim "sjedgingN0Sp"@m@mwt,net wrote:
wrote:

On May 18, 1:49 am, "Bob F" wrote:
Helen4521 wrote:
Can anyone help please? When I was mowing, I ran over a largish stone.
The mower made a noise like the stone was whizzing around with the
blades then white smoke came out of the exhaust. When I stopped the
mower, I tilted it up (only slightly) to see if the stone was still
underneath, didn't see it but saw score marks where it had been. The
blades still move OK. When I started the mower again, it sounded like
a tin can and there was a bit of oil coming out of the exhaust. Have I
done serious damage? What should I be checking next? The mower is
only 2 years old.

Pull the plug wire, and rotate the blade. Chances are, you will find that the
crankshaft is bent, causing one end of the blade to be higher than the other.

With oil coming out the exhaust after hitting a large rock, you have
serious damage and it isn't going to be cheap to fix.

That is probably not true. The oil coming out the exhaust is probably
caused by tipping the engine and getting oil into the crankcase breather
and then sucked into the engine. If the engine is running badly it is
probably because the flywheel key is sheared. Running the engine with a
sheared key will ruin it. Fixing a sheared key shouldn't cost very much.

I'd try to get
a rough estimate over the phone on the repair cost range before
spending money on fixing it. If it's a low to mid-range mower, you
may be better off buying a new one and parting this one out on Ebay.
Start with the engine and tell them you hit a rock and it no longer
runs, all sales final, as is, etc. That usually gets people
interested. I'm amazed at what people will bid on crap like that on
Ebay.

Except that she said it still ran but sounded like a tin can. I'm not
sure what exactly "sounded like a tin can" means, but a sheared flywheel
key or the blade hitting some piece of sheet metal might sound something
like that to some people. Since there was no mention of excessive
vibration I would guess the crankshaft is OK.

-jim- Hide quoted text -

- Show quoted text -

If the oil coming out of the exhaust is due to tipping the mower over
for inspection, how do you explain the white smoke coming out of the
exhaust that suddenly appeared when she hit the rock?

Pretty much the same mechanism. The smoke was the result of a slug of
oil getting through the crankshaft breather. To be any more specific
than that, would require knowing what sort of engine/mower this is. How
would you explain it?

-jim