How To Repair A Seized Stihl 4Mix FS111R KM131R FS131R KM131R

This video shows the damaged caused to the Stihl 4Mix machines like the FS110, FS111, FS130, FS131, KM111R, KM131R, etc. when the engine has been run on straight gas, instead of 2 stroke mix and has seized.
The machine in this video is in daily commercial use, was returned to that task the next morning, and continues to be used without a debris shield.

[@jeffdenney4148]

Sorry sir I see the gasket stuff now awesome job

[@user-jp8tl1wi7g]

You done an excellent job of saving this unit. Great video!!

[@austinado16]

Thank you very much!

[@doglegjake6788]

Excellent video

[@austinado16]

Thank you!

[@w6qd]

I'm surprised there wasn't more straight gas damage to the cylinder, piston, and rings. Every time i see a repair video of a Stihl 4-mix, I'll stick with my Shindaiwa/Echo 2-stroke engines. FWIW, the best weedeater I've ever owned was a 1994 Stihl FS-76, which was actually manufactured by Zenoah/Redmax and rebadged by Stihl. It was a non-EPA'd and I'm pretty sure it was a non-strato engine.

[@austinado16]

RedMax stuff is outstanding! I rarely see it here, because it's not represented by any dealers. Neither is Maruyama, which is also outstanding. Cylinder and piston on these 4Mixers always look fine, as do the crank bearings. It's always that wrist pin that seizes. I intended to show more of the process, but hate having the vids be so long.

[@twocyclesmoke]

@@austinado16 The old Redmax & Shindaiwa trimmers were the best… Now it’s just rebadged Husqvarna/Echo big box store junk. A store had three 1996-1999 bc2600 NOS units. I said I’m buying all three… $250 each was a score. Maruyama is still Made In Japan. Also found a barely used T-27… The guy moved & didn’t need it anymore.

[@austinado16]

@@twocyclesmoke 100% agree. Nice score on the 2600's and the T27! I'm always on the look out for the old-school stuff. Forgot to mention Tanaka, who were also great. They also aren't rep'd here, so it's very rare that I see one.

[@twocyclesmoke]

@@austinado16 Tanaka got ruined by Hitachi…

[@austinado16]

@@twocyclesmoke That's too bad, but doesn't surprise me. I've only seen their old stuff, and very rarely.

[@stephenparchewski1998]

You would think they would just run some oil in the gas before the engine seized instead of after…makes more sense to me, but what do I know?

[@austinado16]

Exactly!

[@jeffdenney4148]

Why no gasket maker

[@austinado16]

If you watch the video, you'll see I'm using anaerobic sealant at 14:40 15:40 and I talk about it at the 2nd time stamp.

[@jeffdenney4148]

@@austinado16 I have the same weed eater runs good but when I use it it loses power any idea what I could do to fix it by the way great video thanks

[@austinado16]

@@jeffdenney4148 It's tough to accurately diagnose from behind the keyboard Jeff. Make sure the air filter is OEM and new. If the carburetor has been replaced by a cheap replica, replace it and the base gasket with an OEM Zama carburetor. Make sure the fuel filter is OEM, not a replica, and it's new. Verify the fuel tank vent functions. Adjust the valves to spec and leave the exhaust valve just a littler looser than spec, so that the valve runs cooler(because it spends more time closed and transferring its heat to the cylinder head). Verify the clutch drum bearing are still good (silent and smooth). Verify the driveshaft is not only lubed, but that it hasn't been run so hot that it's melted the nylon liner that it runs in. Verify the gear box spins silent and smooth, and grease it if it's good. If you run the machine with the debris shield removed and the string long, that will overload and overheat everything: gear box, drive shaft, nylon liner, clutch bearings, clutch assembly, crankshaft bearings, piston, wrist pin, cylinder, and destroy the machine.

[@g-mc4507]

How much does a repair like this cost? I’m guessing it’s still cheaper than a new machine.

[@austinado16]

Depending on overall condition and age of machine, it's usually worth doing.