Offroad Craftsman Backyard Build

Well here's where I'll be showing my slow build of a 90s Craftsman 12hp 6 speed. Runs but surges even after carb clean and fuel filter change, any ideas why? Not a big deal it still runs great. Also, i'm pretty sure it just needs a new belt, but just in case, why does the clutch have to be like 90% out to start to engage?

Anyway, today was the first day I really did anything to it since I got it last week for $50.
Just for fun I ground down the bump stop on the front axle on the left side and a little on the piece mounted to frame and it probably got another almost 1'' of flex. I have another axle off a Yard Machines if I mess with this one too much. Also took the seat off the YM since it has a higher back (I'm 6' 1") and only has a minor crack. Had to mount a little closer since the bolts line up different from the one it had and they sat crooked on the springs but it works for now.
Also, I'm obsessed with seeing 4 wheeled anything flex so be prepared for all the pictures over time.

Day I got it


Changing fuel filter and cleaning carb bowl


That stock flex though


New vs. Old seat


Front axle dropped


Axle ground down

Check out redlinemotorsport his mtd. He is a flex freak to. Haha. The serge is most likely in the idel speed needle try ajusting it

Looks pretty good. Next upgrade is to paint the valve cover a really bright color. As far as the clutch being way out, maybe the belt is streached a little or worn. I'd just let it go if it doesn't bother you too much. The surge may be adjustment or sometimes you miss something when you clean the carb out.

Haha why the valve cover? If anything probably Chevy orange and ya thats what I figured with the belt, its fine until I wanna slowly crawl something to be able to ride the clutch ya know? and I only dropped the bowl to try that first before I undo the whole thing

CornShuck4CE wrote:

Check out redlinemotorsport his mtd. He is a flex freak to. Haha.

I have no idea what you are talking about. lol.

Nice start. Gas petal, bumpers, pulley swap, and tires are all cool things to do. Depending on what route you go.

New vs. Old seat


Your dogs photobombing lol

Ya hoping to do gas pedal and brake lever in very near future since i cant stop unless I use reverse right now. and ya he's pretty good at that lol

Used it to move a snowmobile today to get to camper. 6th gear clutch dump and she was pullin'. Front end was a little light

Wellllll yesterday had her running for a little bit and right before I parked it, it was making a weird popping sound, so I shut it off and went to start it and now it won't start. I tried starting fluid in carb and in plug hole and still nothing. It is getting spark. Just took shroud off flywheel and spun it and it spins with almost no compression so I think it blew the rings. But it wasn't blowing white smoke or anything? And it has plenty of oil in it

chevyguy7783 wrote:

Used it to move a snowmobile today to get to camper. 6th gear clutch dump and she was pullin'. Front end was a little light

You were pulling from a high point on the rear of the tractor.

Use the plate at the bottom that has the hole, and the front end won't seem so 'light'.

^^Wheres the fun in that?

thats OHV right? check your valve lash and push rods

the chain had hooks on both ends and they fit perfectly on the top of the back plate thing above the hitch so it worked and thebeal, right?? haha

ya I think it is I have classes all day tomorrow so absolute earliest to look at it is probably gonna be friday or saturday

higher you hook the more traction you get which is sometimes too much

So the exhaust rocker was very loose, tightened it up to .004, which I found in an online manual for this engine. It still wont start even with starting fluid, its getting gas, but it still seems like it turns over by hand too easy. Also after holding the key to start and letting go I can hear a little pressure that sounds wet coming out of the carb (I have the filter off). If that makes any sense

maybe check the intake rocker

I checked that also it was very close to what it should be. I kept the valve cover off and cranked it a few times and both move fine, no binding or anything

im thinkin the valve is stuck or your headgasket is bad. on ohvs the gaskets do that alot, especially briggs engines.

its a 12 HP tecumseh, best i could come up with was Tecumseh 143-406012 off google.
Just tried a compression tester and it didn't even read anything. Oil might have a gas smell but I can't tell too much since I've never actually experienced it before. Next step would be take the head off?

chevyguy7783 wrote:

its a 12 HP tecumseh, best i could come up with was Tecumseh 143-406012 off google.
Just tried a compression tester and it didn't even read anything. Oil might have a gas smell but I can't tell too much since I've never actually experienced it before. Next step would be take the head off?

Remove the rockers and see if you can spin the valves.

pour a little bit of oil into the spark plug whole and spin it over a few times and then check for compression. it sounds like you might have washed the rings down.