Stihl MS180 C-BE boggs down

MaplesugarRick · 04-16-09, 10:35 AM

I'm having trouble with my Stihl MS180 C-BE chainsaw. The engine boggs down under a load and when just reving the saw. I have replaced the spark plug (properly gapped), rebuilt the carb, replaced the fuel line and the fuel filter, cleaned out the chain brake and the clutch and cleaned the fuel tank air pressure stabilizing valve. Also cleaned muffler and replaced spark arrestting screen.All with no luck. Getting frustrated. Anyone have any suggestions?
Thanks
Rick

fj40charles · 04-16-09, 07:02 PM

Waiting on the Chainsaw KING to reply.

D'Animal · 04-16-09, 08:02 PM

What length bar?

Are you at any elevation?

What size chain? Does the front raker in front of the actual cutter bent over or is it straight up and down?

Have you ever adjsuted (filed) the rakers? Did a shop sharpen the chain or do you do it yourself?

MaplesugarRick · 04-17-09, 06:04 AM

It's 14in bar and chain, with a new chain on the saw. my elevation is 640' above sea level. I do sharpen the chains myself using an Oregon 511A. The rakers are angled low to high with the high end in front of the cutter. They are Sthil chains. I guage the rakers and grind them when necessary.
But I believe my problem is connected to the carb or fuel system, because the saw falters or boggs down when i'm not actually cutting. The engine will rev up when I pull the trigger, but after a few seconds rpms will drop about 1/2 then rev back up again. Almost like I flipped the kill switch for a micro second.

D'Animal · 04-17-09, 06:34 AM

Is the saw new or a few years old?

Michael Hanson · 04-17-09, 06:38 AM

Carb.( 2 cents) the new gas seems to clog small motors Mike

D'Animal · 04-17-09, 06:43 AM

The new fuel doesn't really clog the carbs. The new fuel cleans everything really good and what the fuel cleans ends up in the fuel filter or the carburetor screen.

MaplesugarRick · 04-17-09, 04:14 PM

Found the problem. Using 10x magnifying classes I discovered a tiny piece of fiber partially clogging the high speed jet in the carb. removed it and saw functions perfectly.
Thanks all for your input.
Rick

naturalite · 05-29-10, 01:58 PM

I think I am having the same problem with mine. How did you get the carb off? It's looking a little tricky to me. I have never worked on anything this small. I took it to the shop for repair, thinking it was the carb but they told me I ran straight gas through it and seized it up. I didn't run straight gas through it and it isn't sized up so I am wanting to dig into the carb myself. All help is appreciated.

splitshot · 05-29-10, 02:13 PM

Quote:

Originally Posted by naturalite

I think I am having the same problem with mine. How did you get the carb off? It's looking a little tricky to me. I have never worked on anything this saw. I took it to the shop for repair, thinking it was the carb but they told me I ran straight gas through it and seized it up. I didn't run straight gas through it and it isn't sized up so I am wanting to dig into the carb myself. All help is appreciated.

"Seized" may mean a scored piston/cylinder, have you loaned it to someone?

Welcome to mud BTW.

D'Animal · 05-29-10, 03:03 PM

Remove the muffler. It requires an 8mm or 5/16" nut driver or wrench.

Look in the exhaust port.

naturalite · 05-29-10, 08:29 PM

no never loaned it out. After I got home I remover the spark plug and looked in there and everything looks good. It idles fine but after you rev it up it looses power. I have ran many 2 stroke motor cycles and atv's and feel as though its a carb problem. The muffler looks easy enough to remove but I want to check out the carb. They wrote it up as I ran straight gas through it and seized it. I ask if they checked the carb and they said no. I told them that I ran Polaris gold synthetic in it, which I used to use in my drag bike years ago, service manager says stihl says that that is an unacceptable oil. So I am just wondering how to go about pulling the carb off the easiest way to check out the jets. Thank You for all replies.

naturalite · 05-30-10, 05:59 AM

Just took off the muffler and it all looks good. Don't know how to post a pic of it on here.

D'Animal · 05-30-10, 08:03 AM

By a silver star and you can post unlimited pictures.

Quote:

Originally Posted by naturalite

Just took off the muffler and it all looks good. Don't know how to post a pic of it on here.

Is the spark arrester screen plugged?

What color is the residue on it?

naturalite · 05-30-10, 06:02 PM

Its all clean just a blackish color. A couple of the small holes were plugged with what seemed like excessive oil, but once I blew on it it was clear. All small holes free of residue.

naturalite · 05-30-10, 06:33 PM

Ok I think I can share the pics from this site. Just not sure what I am doing.
sthil pics pictures by naturalite - Photobucket

D'Animal · 05-30-10, 07:30 PM

Now take and post a picture so we can see the exhaust side of the piston.

In you picture the piston is all the way down or BDC.

naturalite · 05-30-10, 08:02 PM

Ok I got it posted. Cant get a good picture becouse of the glare of the piston. piston and cylinder is clean. I will try to figure out how to get the carb off tomorrow morning.

http://s820.photobucket.com/albums/z.../sthil%20pics/

D'Animal · 05-30-10, 08:25 PM

Move the piston up in bore a bit more so we can see the piston below the ring and turn your flash off.

naturalite · 05-30-10, 08:34 PM

It's all clean no cracks no discoloration nothing.

http://s820.photobucket.com/albums/z.../sthil%20pics/