MS-180 fuel/oil problem; saw purchased new June 2022

[SamD]

Hey everyone,

I've got a problem with my little MS180 that I can't figure out. When running, it spits a nasty, oily black mess out of the muffler. It's clearly coming through the combustion chamber since it's so black, but why is this happening? I can only surmise that it's running way too rich. However, with no mixture screws, how is this happening?

Notes: the saw might have 5 hours of run-time; it's one of my homeowner saws for working on my property only, and I've used it maybe 3 or 4 times for light limb cutup.
Spark Arrestor was pulled out when it was new.
It only gets 89-octane ethanol-free fuel with Stihl 2-cycle oil.
The spark plug looks oily and messy (just like a rich-running plug should look).
Air Filter is clean.
New fuel or fuel that's been in the tank for a bit sees no change in the oily mess from the muffler.
Piston and cylinder walls look like they're new (they basically are).
Fuel filter has the same 5 hours on it.

Is this normal? Should I look for a new carburetor? I'm sure Stihl is only going to sell the non-tunable versions, so I'm thinking a Walbro WT-215.

Photos of my "issue" are shown below, but AFTER I started cleaning the mess off the saw. You can see the oily mess in the carb area in photo #1. Photos #2 #3 and #4 show the last of the black mess around the muffler area. Photos #5 and #6 show the back of the cylinder wall and the front of the piston - they're like new...

Thoughts, input, suggestions? Thank you!

 

[Rivets]

Excessive oil coming out of the muffler indicates to me you are using the wrong fuel/oil ratio. Way too much oil. Stihl uses a 50/1 ratio, I use and recommend one pouch of Opti-2 oil to one gallon of fuel. Remove all fuel from the tank, mix a gallon of fuel to the proper ratio, install a new plug and start over. It’s going to take a while to burn off the oil in the muffler, so is going to smoke until you have everything cleared up.

 

[SamD]

Excessive oil coming out of the muffler indicates to me you are using the wrong fuel/oil ratio. Way too much oil. Stihl uses a 50/1 ratio, I use and recommend one pouch of Opti-2 oil to one gallon of fuel. Remove all fuel from the tank, mix a gallon of fuel to the proper ratio, install a new plug and start over. It’s going to take a while to burn off the oil in the muffler, so is going to smoke until you have everything cleared up.

I'm using Stihl brand 50:1 ratio oil with non-ethanol fuel. I am no stranger to Stihl 2-strokes and have had dozens of them, work on all of my own equipment, even rehab old and damaged Stihl equipment as a sideline.

This is something different. I'm OCD with my fuel/oil mix cans: I only use 1-gallon fuel cans and the Stihl oil bottles made for 1 gallon. One bottle for one gallon of gas - that never changes...

Any other ideas?

 

[SamD]

Sorry everyone - forgot to attach the photos, but they're in the post now

 

[Rivets]

I’m then at a loss. The only place where oil can enter the cylinder is with the fuel.

 

[StarTech]

That should be a Zama C1Q-S57A or the current Stihl replacement.

 

[SamD]

I’m then at a loss. The only place where oil can enter the cylinder is with the fuel.

I'm with you! This one has me puzzled. I've read of folks changing the mixture settings via internal adjustments to the carburetor, but that is outside of my wheelhouse - I can rebuild the carburetor, but I don't like tinkering with all those little parts to begin with. Making changes to them is not going to happen.

I'm really thinking the carb is at issue, but I can't say why I think that way. There is something just wrong about putting a non-adjustable carburetor on a carbureted motor, so I'm likely going to wait a few days for replies to this thread and see what folks come up with.

 

[SamD]

That should be a Zama C1Q-S57A or the current Stihl replacement.

It is a ZAMA on it from Stihl: C1Q-S152E - came that way from the dealer less than 2 years ago

 

[ILENGINE]

5th picture looks like scoring of the piston. What does the cylinder wall look like through the spark plug hole.

 

[SamD]

5th picture looks like scoring of the piston. What does the cylinder wall look like through the spark plug hole.

There's no scoring of the piston or cylinder walls. I've looked at it through the intake side, the exhaust side and through the plug hole - my camera picks up every single minute detail in an object photographed.

I know scoring can happen fast, and I've repaired saws that have severe scoring. This motor has 5 hours on it if even that. It's been used only a few times, but each time (THIS INCLUDES THE FIRST TIME I USED IT), it dribbles oil out the muffler, even spits it out in some cases.. :-(