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Hybrid Lawnmower *grin* (or, My Adventures into the American side of the Toolbox!)


Daeron

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My lawnmower sucks.

 

It is an ancient craftsman bagger model, that has had three or four different engines on the frame over the course of its life. My landlord/roomate has had it forever, and has kept that one alive because he had and used the bag for it (the bag is huge) and we compost all of our yard waste and fish remains. The thing is so godawful looking that I will NOT even post a picture of it here. One front wheel is being held on with tie wire. Bad.

 

It runs like a top, but its falling apart! So, somewhere Fletcher (my landlord) picked up this really nice Craftsman self-propelled mulching/bagging mower, I think from the dumpster at work?! I don't know.

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Its got a 6.75 horsepower Tecumseh engine on it, 22" cut. Just, your standard, MODERN, pretty nice self propelled mower. Nothing special.. but better than "the beast" with the broken recoil (we had to wind the rope back up manually :rolleyesg)

 

We rebuilt the carburetor on it, replaced the spark plug and the air filter, and it ran like a top. Except, it had an oil leak REAL BAD, and was about ten times louder when you stood on the non exhaust side of the engine, than when you stood on the exhaust side. Rod Knock, anyone? So, no go on the new mow.

 

Fast forward about a year to last week. My dad emailed me, saying that he had his "old" mower that he could give me, a five horse techumseh engine, it just needed a carburetor. He had rebuilt the carb on it completely, it looks beautiful.. it should run great... BUT, the carb will not run. He "got around to" rebuilding the carb on another mower he had (identical to my craftsman, actually) and wanted to know if i wanted this engine.

 

Since I knew I had a recently rebuilt carburetor, I jumped on it.

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My dad also was aware that I had a need for some sort of lawnmower related parts.. we are kinda "buddies" like that, neither of us buys lawnmowers, we find "broken" ones and put them together into working ones. Its a pasttime as much as a money saver.

 

Anyhow, I became the proud owner of a formerly self propelled, non running murray.

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Of course, as soon as I started taking things apart, I discovered that in the last year my nice, "rebuilt" carburetor had gotten all fouled up with junk and nastiness... wonderful. Re Rebuild time!

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Eventually got it taken care of, and in the course of this discovered that the bore on the 5 horse murray carb was about 60% of the size of the bore on the craftsman carb.. I am imagining that a large amount of the horsepower increase is from this bore change alone. The craftsman also had a different cylinder head, with the intake port on the bottom, and the craftsman intake manifold, as a result, had a downward slope to it.

 

Other than that, the two engines were identical. The air filter setup, and the carburetors, were somewhat different though. There was some sort of vacuum line? coming out of the rear of the block, and on the murray it went into the air filter housing; whereas on the craftsman it went directly to a second hose barb on the carb. This barb appeared to lead into a red straw that snuck through the bore, and out into the air filter; without the air filter this carb will NOT run. So, step one (after the carb rebuild, heh) was to remove the engine cover, air filter, oil filler and gas tank assembly from the murray and replace it with the pieces from the craftsman. The craftsman recoil had a busted rope, so I just used the murray recoil. Lo!!

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And Behold..

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Yah, the 5 horse has stripped exhaust threads, must JB weld that in the near future. But that is the same motor that was on the red frame.. with the carb and trimmings of the cratsman on it. It started fine, but wouldn't keep running after it started. The air filter was sopping wet, and I chalked it up to that, end afternoon 1.

 

So today I got off from work early, and went out to beat my head against it, and sweat some more. (a lot more, actually..) I began by confirming that it ran good with a dry air filter, and set to removing the engine from the craftsman, examining the drive assembly (this is the first self propelled lawnmower I have had my fingers into) and making sure everything was going to be a direct swap as anticipated. Really, it is amazing how rarely I have seen two lawnmowers whose engines could not theoretically at least be swapped. It takes a serious oddball brand to be different.

 

 

There were several minor issues that I wont bore you with details on; suffice it to say that I had to get inventive to retain both the blade brake, and find a way to activate the drive mechanism, because the cables that I had and the levers that I had did not all match up. In the end I had to kinda pinch the handle assembly from the murray, and put it on the craftsman, to get it to work right. I also had to use the original craftsman blade brake cable on the drive, and use the murray brake cable on the blade brake. On top of the "accesory witching", the blades had different methods of staying locked to the output shaft, and the blade for the engine we used was shot (and smaller) so there was a minor bit of ingenuity there as well.. but otherwise it went easy as pie.

 

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And so here we are. Back to where we started, appearance-wise anyhow. There are two covers still uninstalled in these pictures, because they were taken right after mowing the first trial patch. As soon as I had this thing together, on the very first successful start, I pushed it out for a victory lap around the weeds in the back. Runs great.

 

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You can see some fresh gore on her, from her battle out in the yard. Aint life grand?

 

here is a gratuitous shot of my admired and appreciated assistant:

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and the aftermath:

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I really want to paint the deck, now. I DEFINITELY plan on removing the Craftsman badging and stencilling DAERON on there somewhere, ad the very least.

 

I am not bragging about my insane skills, or anything.. Just sharing something I thought might be interesting to some of you people walking a less unusual path than I :-D To those who understand what I did, and have done the same, I salute you! This kinda tinkering is fun, and beneficial; I take garbage and turn it into a $300 lawnmower

 

And finally... What I am about to say I mean on so many different levels....

 

THANKS, DAD!!!

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I've got a 12-year-old MTD mower that I kept 'cause I liked the deck -- its self-propelled, and has one lever to adjust the height of all 4 wheels. I have worn out the original 5.5HP Techumseh and for a I while ran a used 5HP Briggs that just needed a new flywheel shear pin. Later the coil went bad and I didn't have a cheap replacement so I splurged on a new engine

Currently it has a 6.5HP Honda that I bought mail-order from Northern Hydraulics. It's like getting a new mower for $120.

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You know what's sad? What's sad is that I was really into the story. I'm reading, and I'm kind of muttering to myself "So what's he going to do with the - hey, is that a new carb on that motor, or the old one... wait ... Oh, I see! Hmm, he's going to have to do something with the self-propel system ... Oh, cool! That's cool! ... "

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bitchin, I knew I would get SOME sort of positive response.

 

As for the convention...

 

I'm poor enough to be rebuilding a junk lawnmower. I think that says enough, heh.

 

I will make it to the conventions when my posts have something to do with my car, deal? :icon46:

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I'm poor enough to be rebuilding a junk lawnmower.

 

That's how you learn: when you are too poor or too cheap to buy new, you tinker with the old stuff to make it all work. "Ingenuity is the mother of invention," and the dead beat dad of tinkering isn't too far behind :D Good read!

 

 

Davy

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Had a neighbor who put a 125cc two stroke Yamaha YZ engine on his mower. First time he ran it up to 5,000+ rpm the steel blade snapped at the center bolt and the two halves shot through the sides of the mower. One blade stuck 4" into a railroad tie and the other shot into the garage and skewered a metal trash can.

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Had a neighbor who put a 125cc two stroke Yamaha YZ engine on his mower. First time he ran it up to 5,000+ rpm the steel blade snapped at the center bolt and the two halves shot through the sides of the mower. One blade stuck 4" into a railroad tie and the other shot into the garage and skewered a metal trash can.

He needs to get a forged blade then I'd say. Then get it balanced. Wouldn't have to slow down from a steady jog with that :D

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