From the files of "You Just Can't Make This Stuff Up"

[JimN]

This happened while I was dealing with the skid steer. F-in law let a neighbor use his chainsaw. He brought it back from said neighbor and told me the chain brake was stuck. Ok. I'll take a look at it. I thought it might gummed up from lack of cleaning. Noooooo.

Didn't occur to me that somebody would try and cut wood with the brake still on. I'm surprised it didn't catch on fire.
Housing cover and brake band were fused to the clutch cover with melted plastic. Clutch cover needle bearing was destroyed. Top half of oil pump drive gear was gone and the clip that drives the gear was fused to the cover plate it's sitting on in the picture.

 

[cl350rr]

I have seen this very thing before so it does happen

 

[sparkwizard]

I bet it didn't cut very well since it was fighting the brake.
Give it to the fool who borrowed it and buy a new one.

 

[JimN]

Once I cleared all the crap out of the way I was able to start it. I found all the parts I needed from ebay. Came out to a little less than half the cost of a new one.
Could have bought cheaper parts but I just couldn't put no name chinese parts in a Stihl.
I figure if he still wants to buy a new one I'll take it off his hands for the cost of the parts and either keep it or sell it.

 

[sparkwizard]

Were you able to question the guy who borrowed it? He didn't think anything was wrong, didn't smell anything?
You would think a grown man using a chainsaw would be reasonably sober, right?

 

[JimN]

I don't think I want to know.

 

[sparkwizard]

Your FIL doesn't have a still out in the woods, does he?

 

[JimN]

Well a few days, a couple of youtube videos, and $236.00 in parts later, the ms251c be z is back together and running fine.
Had to buy a housing, right side housing cover, oil pump w/worm gear, brake band, and clutch assembly.
Only had 2 issues, 1 of which is just stupid. When I went to take the nuts of off the carb, the 1/4 drive deep socket wouldn't fit into the plastic holes of the air filter housing, only went in a little bit then got stuck. I tried a 5/16 and 8mm. I wound up grabbing an old socket and ground the sidewall down.



The other isssue. Since the housing mounting bolts also hold the engine together I decided to do a leak test once I swapped that part out. I have some 1/8 rubber matting to make sealing gaskets for the intake and exhaust ports and I fabbed up an intake cover plate with flat 3/16 steel and a drilled out zirk nut to hook up my mityvac.



The vacuum part went fine. Pumped it down to 15" hg. Held it for about 20 sec. When I went to switch the nob to pressure my mityvac jacked up so now I have to rebuild it, kit is on order. Since the engine case held vacuum I'm wasn't too concerned. The rest of the fix went fine.
Due to the design of the saw I didn't have to take the rubber intake or the plastic intake backing plate off. Good thing to, that looked like it could be a pain to get back on.











Here is the finished product. I like the spring assisted pull cord but that chain adjuster set up seems like an accident waiting to happen.

 

[sparkwizard]

When they work, they are great. (BMW, Mercedes, VW-Audi) But when they don't work, they are overengineered German junk.
That is my professional Master Mechanic opinion. Glad you got it working. Good job, Friend!

 

[ZR9B]

I got in a pissing match with neighbor Cliff, because I wouldn't let him use my shit......His shit was always broke. His shit looked just like that.