Rebuilding stihl ms361 top end

[CRudy]

Hey guys, just picked up a saw from my work that was diagnosed as 'blown up'. Got it home and took it apart and the piston and cylinder was scarred up pretty bad. However everything else down in the bottom of the engine looks fine. I was thinking of ordering an aftermarket cylinder and piston kit from Hyway small engine. I'm not 100% sure on how the saw got scarred up, it looks like something got into the cylinder scraped it while it was running, plus some of my co workers are pretty rough on a saw which probably helped with the wear and tear. I was just looking for some opinions from some people with experience on if its worth the trouble and if there is anything else I might should take a look at while ive got it apart. Thanks!

 

[Ozhoo]

It's a great saw and well worth fixing. Post up some pictures of the piston and cylinder and we'll guesstimate what happened to her.

 

[CRudy]

Here are some photos of the piston and cylinder, hopefully they come out well, i am having some trouble trying to upload photos

 

[Ozhoo]

Holy smokes she got hot! That rod looks like a rainbow. Cylinder looks like it'll clean up well enough to run again.

 

[Ozhoo]

I'd split the case and run all the parts through the dishwasher. New crank bearing and seals, clean up the cylinder, new piston/rings and give all the rubber a thorough exam.

 

[Wood Doctor]

Is it worth the trouble? If you put a gun at my head and said I could only keep one of my 14 saws and all the rest have to go, the MS 361 would be the keeper. Take it from there.

 

[cedarshark]

You have melted aluminum on the cylinder walls. I see 1 place below the left side of the exhaust port that may/may not clean up. If the scratch is below the nikisil plating, the cylinder is pretty much done. Your piston is trash and should be replaced w/ an OEM or Meteor if you want to save a few bucks. Do a search for cleaning a cylinder with acid or mechanically with a Dremel tool. You also need to determine why the saw was run lean and overheated.

 

[67L36Driver]

The big end rod bearing got extremely hot.

Enuf to turn the steel blue.[emoji15]

IIWM (if it were me) I'd put in a replacement crank assembly, new or used.

 

[Wood Doctor]

The big end rod bearing got extremely hot.

Enuf to turn the steel blue.[emoji15]

IIWM (if it were me) I'd put in a replacement crank assembly, new or used.

I have to agree. Bearings and seals are probably shot also. Look at how far out of alignment it all is. Let's hope that is all that is wrong besides the rest of the top end. I can't even imagine what caused all of this. Frankly, it gives me the creeps.

 

[CRudy]

Ok I wasnt sure if that coloring on that rod was normal or not lol. Do yall have a ballpark idea of how much a crank case splitter is and crank seals, or a good website I could look at ordering them from? Thanks for the replies

 

[cedarshark]

There are guys around that split cases with homemade tools, but I think the most successful ones are the "c" shaped splitters you see on fleabay for about 80 bucks. You may be able to find a case and crank assembly (used) for a resonable price as an alternative. I am against aftermarket cranks and cases but some people have success with em and some don't.

 

[a. palmer jr.]

Don't skimp on the fuel system when you get the engine done, clean the carb real good and kit it and check the fuel line for leaks. Also, don't forget to clean the muffler, stuff comes into the engine from that side too.

 

[earlthegoat2]

I have some 361 engine parts. Have a good piston for sure. Probably a cylinder as well. Used OEM.

 

[325ed]

i put nwp big bore 49mm kits on / the last one i ordered caber rings / aftermarket works fine for firewood /

 

[earlthegoat2]

If the thing really needs a new crank, rod, and bearings, then it is not worth fixing from a monetary perspective. If you want a fun project though, then go at it.

I have heard that bluing on the rod is normal from the heat treating process. Never got anything definitive on that though. I do know that when a 2 cycle is run lean, exponentially more damage is done to the top end from loss of lubrication and heat than to the bottom end.

 

[Mike Whitmore]

If your not gonna rebuild it let me know...im unemployed right now and could use a project saw...looking for an old 036 or 360..to do it on..

 

[Mad Professor]

1st pic looks like some sort of metal made it's way through the P/C.

P/C and maybe crank parts to fix it.

Maybe find a donor saw that got squashed by a tree.

 

[Rick Stephens]

If I couldn't figure a way to put OEM parts back on it and stay inside value, I'd go aftermarket like Meteor or Hyway in a flat second. Nothing at all wrong with doing that as long as you vac test it and go through the carb before running.

 

[Mike Whitmore]

I think i’d probly replace the crank..i’d be afraid the bearing in the crank under the connecting rod was damaged

 

[Mad Professor]

If I couldn't figure a way to put OEM parts back on it and stay inside value, I'd go aftermarket like Meteor or Hyway in a flat second. Nothing at all wrong with doing that as long as you vac test it and go through the carb before running.

Please don't, if you try to fix it, go Chi-Com.
Italy is better