Saturday, June 7, 2014

Roadside Find -- A Sears Craftsman 20" Lawnmower

Well, what have we here?

Something I've never seen before -- a Briggs & Stratton engine with a chrome exhaust pipe.

That appears to be a 1/2" pipe shower head stem. It's pretty sharp looking, actually.

The kill switch is a little less elegant.

At least it's unambiguous.

I don't mean to make fun here. Whoever made those repairs was working with what he had, and came up with perfectly useable functionality; there's no shame in that.

That said, there is room for improvement, and since I have little better to do, I'll go ahead and make improvements.

I'll be back when I've gotten a proper muffler for the thing.

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The Muffler -- MONDAY, JUNE 9, 2014

Here's the correct muffler in place, looking as it should.

That's a Briggs & Stratton P/N 394569S muffler. It has a 1/2" NPT (National Pipe Thread) nipple that threads directly into the engine's exhaust port. That muffler can be used on any small engine with the same exhaust port thread, so long as it fits overall.

No thread sealant is needed, but it's a good idea to apply an anti-seize thread compound[1] to the nipple on installation.

With the proper muffler on it, the engine has a more civilized exhaust note.

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The Kill Switch -- TUESDAY, JUNE 10, 2014

Here's what I came up with for a kill switch.

That looks better; now the mower has a 'dashboard'. Also, one doesn't have to reach right to the engine to switch it off.

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The Blade

Here's a view of the blade off the mower.

Hmmm. Not only is the blade duller than a 2" x 4", it's bent. Lawnmower blades are really tough; how one can bend a blade in anything remotely resembling normal mower operation is beyond me.

Anyway, the blade is beyond redemption, and it's supposed to be a mulching blade -- I'll have to replace it.

New Blade

Canadian Tire had just what I needed -- a 20" universal-replacement mulching blade, with adapters to fit many makes of mower.

The only adapter I need is that small one at the extreme left. I'll soon have this mower in fit condition to cut grass.

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A Slight Problem With The Blade

In the above photo, note the slight down-sweep of the blade's ends.

When installed in the mower, the down-swept blade ends were almost peeking out from beneath the lower rim of the mower's deck -- not ideal.

The only way to elevate the blade was to elevate the entire engine, so that's what I did. I bored out three 3/8"-16 hex nuts for spacers, and came up with this arrangement at each of the engine's three mounting points.

That bought me about 1/2" of extra blade elevation, which put the blade's height within the deck more-or-less where it ought to be. The gap created between the engine and the deck proved not to be any problem at all -- there was no adverse effect on the mower's behaviour.

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The Fuel Tank Cap

The fuel tank cap still screwed on, but it had a nasty dent in it. I bought a new one. (Briggs & Stratton P/N 497929.)

I suspect that dent resulted when someone left the cap off on the grass and ran over it with the mower.

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Finishing Up -- SUNDAY, JUNE 15, 2014

Further routine items that needed attention:

  • Air filter and carburetor/fuel-tank dismantling/cleaning. (The carb should get a new diaphragm. See this post for information on that.)
  • Spark plug cleaning and gapping.
  • Oil change.
  • Wheels oiled.
And with all that done, the mower was ready to go to work. Here it is taking a break after a job done.

The engine's compression/power isn't quite what I'd like it to be, but as a light-duty homeowner's mower, the machine is still perfectly serviceable.

Yard gear like this lawnmower can be kept going almost indefinitely with nothing more than ordinary maintenance and repairs.

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[1] The stuff I use is Molykote Anti-Seize Thread Compound that I bought long ago. I don't think that product is available any longer; the compound goes a long way, and my ancient 1 lb. tin of it is not empty yet. A reader kindly informed me of Permatex No. 80078 Anti-Seize Lubricant. That product is available, and came highly recommended by the reader.

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