I have straightened bent crankshafts on lawn mower engines that I got as
"junk"
because nobody wanted to fix them. I used my 20 ton press, supported the shaft
at the ends, and kept nudging it until I could detect no runout. The problems
are several: if the material is soft enough to bend easily in the first place,
it will probably bend again the next time the blade hits something; it has to
be
absolutely straight and checked with a precision runout gauge in a drill press
or lathe or it will be out of balance and tear the bearings/seals up; and
finally, as you suggested, it is usually easier to replace the whole engine (or
even the whole machine), as skilled small engine mechanics are hard to come by.
At $60/hr shop rates, nobody is willing to pay to have things fixed. When I did
it, it was because my investment in the machines was zero, and I figured I had
nothing to lose by trying. The engines ran well enough when I was done, and I
was able to sell the mowers for $25 or so to folks who couldn't afford brand
new.
I should point out that the bent crankshafts were on Sears (made for them by
Tecumseh) machines. None of the shops in our area will work on Sears machines
except to change the oil, spark plug, and air filter.
Mike
Mullen, Tim wrote:
> The list has been quiet for a few days so, I'll ask a question.
>
>
> As for my lawn mower with the bent crank, I asked around
> at a couple of lawn mower shops in the area about
> straightening my crank. They looked at me like I was crazy.
> They don't do it in this area, and never even heard of it
> being done... One of the disadvantages of living in the
> "High Income", Northern Virginia area - people are so used
> to throwing things away and replacing them (although my new
> lawn mower works *much* better than the old one)... 8-)
>
> Tim Mullen
>
>
--
________________________________________________________________
Mike Sloane
Allamuchy NJ
(msloane@att.net)
<http://www.geocities.com/mikesloane>
Letter writing is the only device for combining solitude with good company.
-George Gordon Byron, poet (1788-1824)
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