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rebuilding lawn mower engine / 1st time / need advice

Scottintexas

Jetboaters Admiral
Staff member
Messages
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Location
Corinth, TX (DFW)
Boat Make
Yamaha
Year
2007
Boat Model
AR
Boat Length
23
So after my success (so far) with fixing my mom's flooded John Deere mower I've gotten much braver.
My neighbor is getting older and he can't cut his grass with push mower because it hurts his knees but a big rider is to much so I was trying to help him out.
I found this little beauty, garage kept, supposedly ran but no motion (the guy led me to believe it was a belt/transmission issue), the battery was dead and gas tank empty but since it was only 10 minutes from my office and $10. (it was a very nice neighborhood) I figured it was worth a gamble.
20161001_150243.jpg

after a quick diagnoses at home I found it had no compression,
I pulled the head and found the piston was not working properly. It would go up but not back down.

20161001_100530.jpg

20161001_100436.jpg


I really got brave and removed the engine and took the sump off to look inside and found

20161001_150049.jpg


The crank has some scoring on it, enough to feel sharp on my fingers,

20161001_150447.jpg

20161001_150549.jpg
The cylinder seems very smooth.

At this point I'm into it for $10 and about 5 hours of a good learning experience so I'm very happy and could push it to the curb with no regrets.

since this is just a lawn mower, does the crank have to be "like new smooth" to work and live a worth while life?

Youtube is great for watching and learning, but stinks for asking questions,
Is this easily rebuilt?
The crank would be $200.
piston kit $50.
connecting arm $50.

Could I get away with just connecting arm?

A new engine would be about $450. I really doubt I would spend that much and don't think I would spend $200 on the crank. I want to get buy as cheap as I can since it's not a very good quality mower anyways but want it to last more than a year.
 
Might just be cheaper to cut his lawn! Sorry I couldn't resist.
 
Its hard to tell from your pics if the crank pin is rough, or just the remainder of the bearing. Do they sell oversized bearings for that engine? If that is the crank surface the engine would not run long, and would ruin whatever new parts you did put in it.
 
Wow! You got way more free time on your hands than I do!! I'm envious. If it were me, I'd buy a new engine from Harbor Freight.
 
If that picture is the cranks connecting rod journal, the crank is toast. A replacement is best, no oversized bearing without refinish work to the journal from a machine shop will last and will destroy any bearing and connecting rod you put in. Just my $.02.
 
Wow! You got way more free time on your hands than I do!! I'm envious. If it were me, I'd buy a new engine from Harbor Freight.
And get the one with more power to boot!
 
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