70's Magnesium Craftsman Push Mower Model # 131.90300

[wrecked]

A few years ago someone gave me an early/mid 70's alloy deck Craftsman push mower, it got lost for a bit in the shed but I liked how easy it pushed. I re-discovered it while cleaning out the shed last month and decided to get it running again.
The original motor was swapped for a Briggs and Stratton 3.5hp, which I'm told is for the better?
I got it running as found pretty easily, cleaning the points was all it took to make it run. The blade was like new, I replaced the air filter foam, spark plug, coil, switched it over to Magnatron and abandoned the points, after mowing the lawn a few times with it I decided to make it look a bit better. I stripped it down bare, glass beaded the deck shell, and all hardware, replaced the recoil cord, rewound the spring properly, then gave it some fresh paint. I had a can of copper/gold hammer tone so I gave the deck several heavy coats and I painted the motor with a few coats of low gloss black. A buddy took the handle and powder coated it in bright silver.
I knocked the bearings out of the wheels, sandblasted off the rust, filler primed and painted each one and relubed the bearings as well.

Here's a before and after:


The deck has a through hole below the muffler, from what I read these had exhaust that went out the bottom on the original Tecumseh engine. I have a few older Tecumseh engines, including a 4.0hp off a similar age Sears mower but its exhaust does not exit downward. It appears that the exhaust on these had a tiny tail pipe that came out in front of the muffler and turned down through that opening. I think as a mower its likely better have the BS engine and I'm fine with that part but since I have the right motor, I could make a custom muffler that goes out the bottom. Of course I could also do that with the BS engine too.

This looks like the same mower in the 1974 catalog:

I am missing the rear rock pan and the outlet baffle or chute, or the bag assembly. I don't much care about the bag but will keep an eye out for the side discharge chute. I do kind of like how well it disperses the cut grass though vs leaving little piles of grass like most newer mowers do.

 

[Auto Doc's]

I would not make an exhaust exit through the hole in the deck. That would be risky with dry grass clippings. I do not think that was an exhaust hole anyway. Mostly like it was for putting a bar through to hold the blade so the center bolt cold be loosened and tightened as needed.

Nice job on the finished results.

 

[vintagerust]

I had one of those back in the early 80's, got it from a neighbor who passed away at the time. It was red not gold or copper with some sort of bicentennial decals on the deck, so it was likely 1975-76 or so. It had a Tecumseh motor, they called it 6.0hp I believe but it looked like an other 3.5hp Tecumseh that came before it. It said 'develops up to 6.0HP'.
They only made that deck for about 4 or 5 years. They worked well and were super light.

The muffler was a box with a little 3/4" diameter tube the turned down and went through the deck, which had a grommet in it. The motor was rubber mounted too and without the grommet that pipe would rattle around in the hole. The mounts were bad on mine and the muffler wore through the grommet and into the deck and finally broke off the little pipe. It was available yet in the mid 80's but they wanted something like $18 for it so I opted for a screw in muffler instead. The hole let some debris come though but it let more drop down keeping the top of the deck clean. The Tecumseh blew up a few years later, it just stopped one day. I didn't hear a thing but when I looked there was a hole in the front left corner of the block about 1/4" across or so.

When I opened up the motor I found a piston rod in about 20 pieces. No other damage just the block hole and shattered rod. The piston was about half way up, no damage. I cleaned up the motor, found a used rod for it, had a neighbor weld up the hole in the block and it ran again.

It was good for another couple hears till my ex at the time managed to hit a hit a concrete gutter drain with it. I thought the flywheel had just sheared but after a new key, it still wouldn't run right. A tear down showed it had twisted the crank about 8° top to bottom and cracked the bottom of the engine block where the crank went through.

The next summer it had a 3.5hp Briggs motor off a junk Murray mower I trash picked. The original motor is still out in the shed somewhere, still needing a crank and bottom half of the block. I probably have one but was never a big fan of Tecumseh motors.

It finally got replaced with a newer steel deck mower after the deck just had gotten too many holes in it. After 20 or so years of use it looked like it had been through a gun fight there where so many holes in it.

 

[wrecked]

I have a Tecumseh here with that muffler, it bolts on witht wo through bolts. the muffler's only outlet is toward the front of the engine, there's a short elbow that pokes through the mounting deck. The one here is on a Craftsman Roto Hoe and Roto Spader with a Tecumseh motor, I have two, one with the Tecumseh, one with a 3hp B&S motor. Both are nearly identical but built by different brands, one is Early MTD, the other General Products built. (785 model number).

I don't plan on putting the Tecumseh motor back on it, it would be different if it were a museum piece but I intend to use the thing.

 

[wrecked]

I found this today, anyone every heard of Yardmaster mowers?
Its new enough to have a flywheel brake though, so its likely from the 80's or so.
It looked like they threw it away after buying a new battery mower, there was a box and owner's manual there for a Chinese rechargeable mower from Amazon, it had good gas, a new blade, all the wheels are good, the cables are all good, it only needed a fuel line from the tank to the carb, it had turned to goo and collapsed. I stuck a new piece of hose on it and it fired right up.

I thought at first it may be a donor for the Sears but t too new and certainly not an upgrade in any way.


Its not pretty but it runs and cuts, can't imagine throwing away a running mower that still works, especially not to replace with a piece of plastic Chinesium.

 

[vintagerust]

I pretty much stopped picking up the rough one's like that, even if it runs like new you won't ever be able to sell it. People around here won't touch anything that don't match the one's on the floor down at Lowes or HD, then they won't pay more than $10 maybe $20 for one because they don't have cash.

 

[wrecked]

I grabbed it thinking that if nothing else its a set of wheels, other than the rusty look about it, the thing is actually in decent shape, it had a clean, newish looking air cleaner foam, clean oil, a new plug, and all the cables are good. The blade looks new. I suppose if I took the time to hit the handle with some chrome cleaner that too would clean up.
I mowed my back yard with it Sat afternoon, its light, small enough to cut around the man obstacles, and it starts on two pulls. The recoil rope is a bit short, but other than that its good. For now, I dumped the gas out of it, ran it dry and stuck it on a shelf in the shed.
Three more clunkers showed up today, the red Troy Bilt runs and has a bag with it, the JD runs but vibrates bad, the one end is missing off the blade, and the red Craftsman is junk, full of water, and looks like its been submerged. The carb, rear wheels, handle and small parts though can be used elsewhere.


5hp Quantum motor on a 21" Troybilt Runs as found, even has a bag. the blade brake cable is missing, but a zip tie fixed that for now. I'm perfectly fine with just unplugging the spark plug to shut it off. It actualy runs quite well.


JD J63, 6.75hp. Runs, missing top cover but I've got several outback to make it complete. Has vibration and piece missing off the top wing part of the blade on one end.


Another 6.75 hp but on a Craftsman, this one is parts, the motor was full of water, it has no compression and the rear wheel brackets are bent, the deck is rusty, the front drive is seized, and the front wheels are stripped out. It will get broken down for spare parts, it did have a new blade though which will fit the JD.

All came from the same scrap guy, he swapped them for some other scrap metal I had to get rid of.
I'm not sure what's up but push mowers are coming out of the woodwork lately, I've gotten 20 or so this spring off the local scrap guys. Most ran as-found, others needed only a quick carb clean or blade. I think the red craftsman is the first junk one I got. There's several more of the JD and Craftsman too,
I don't mind something for basically free but they don't sell and I can only use so many. As it stands now I have a solid rotation of mowers, if I used a different one each week, none would get used more than once all year.
I was talking to one neighbor who was looking at the magnesium deck Craftsman and he kept asking me how I could use such an old mower, he said it looks too square to mow the lawn with. As if aerodynamics affected a push mower. Comments like that are what I get of CL and FB too.
I had a guy ask if I had any blue lawn mowers.Then went on to message me back and forth about the benefits of the color blue.
Another wanted a Honda no older than 2024 but didn't want to spend more than $25.
Another message off CL wanted to know if I could mail him the reel mower I had listed. He was 10 miles away so I offered to deliver it, he refused because he didn't want strangers at his house, and he doesn't go to stranger's homes to buy things. I told him shipping would be $100, he went away. I'm not boxing up a mower for free to ship it a mile away because some grown man can't put on his big boy pants and go buy a mower he wants. Its either that or he knows if he pays by PayPal he can charge it on his CC vs cash in person.