MS660 Woes

[MEATSAW]

Hello evening crowd. So I posted a few days ago about an MS660 that I have at work that people were complaining about. The report was that when it was turned sideways it would die. From your responses my game plan would be do the checks that we all know and love: fuel filter, lines, carb, etc. And if that didn't help then I would look into replacing the seals.

So today I had some time to work on it and figured the first order of business was to get it started and go from there. And you guessed it: couldn't get it to start. Now comes the funky part. I noticed a black fluid all over the front of the saw. I quickly realized that a substantial amount of black ooze (that was mostly gas?) was coming out of the muffler! The more I pulled the starter rope the more black oozed out the muffler. So I pulled the muffler off and checked out the piston and cylinder. A nice ring of black ooze around the cylinder above the piston. I also noticed something peculiar: as I moved the piston up when it passed the exhaust port it would start bubbling and fizzing around the rings.

So what the hell is going on with this saw?

 

[HILLBILLYREDNEC]

Picts of the stuff would help. Thinking you need to pull the slug and jug and clean the substance out the slug and jug..

 

[atvguns]

sounds like the crank case is full of something, bar oil maybe mixed with gas have you looked to see what is in the gas tank.

 

[blsnelling]

Sounds to me like it's badly flooded. Pull the plug and let it set over night, put a kit in the carb, install a new plug, and fire it up.

 

[fearofpavement]

For whatever reason there is an excess of fuel going into the cylinder. I think the black goo is the fuel mixing with carbon and other residues and dissolving them. May want to empty the tank and see what mix is in there. ie, did someone put oil in the fuel tank. (I have no personal knowledge of this happening but have "read" about it)

The bubbling is probably just the compressed air from the cylinder leaking back down through the rings.

 

[MEATSAW]

Sounds to me like it's badly flooded. Pull the plug and let it set over night, put a kit in the carb, install a new plug, and fire it up.

I would agree with this diagnosis, but this begs the question: how did it get so badly flooded? No one messes with the carb adjustments and I checked and it was properly adjusted. Maybe I need to check the spark plug/ignition.

The bubbling is probably just the compressed air from the cylinder leaking back down through the rings.

I have checked out lots of P&Cs through the exhaust port and never seen it bubble around the rings...

 

[MEATSAW]

Oh and I definitely will be putting some fresh fuel in it straight away. If only this was my personal saw it wouldn't be such a mess.

 

[stihl038x2]

OK......I'll take a "stab". I just rebuilt an 088 & had carb issues, wound up being the metering lever spring was wayyy to strong ( pop off test revealed this). Anyhow, got that solved & it ran for a while then started flooding out BIG TIME, similar to your problem. Instead of tearing into the carb again I looked things over & found the tank vent (stupid little "umbrella" inside tank at top) wasn't working properly anymore, replaced it and "voila", runs like a champ !!!
So bottom line, it was pressurizing the tank & COMPLETLY filling the cyl. and oozing out like yours.

Steve

 

[wheelman]

You may want to pressure test the crank case and make sure that you dont have a leak between the case and the oil tank.

 

[MEATSAW]

I really hope its not something requiring major renovation. For a saw under 3 years old at its price point I'll find it a little ridiculous if its a major problem.

 

[blsnelling]

I really hope its not something requiring major renovation. For a saw under 3 years old at its price point I'll find it a little ridiculous if its a major problem.

Any kind of machine can break. Happens to all makes. That bubbling is just all the excess fuel around the rings.

 

[stihl038x2]

YEP.............. major $$$, have your boss contact me, I need a "parts" saw.

Steve

 

[MEATSAW]

YEP.............. major $$$, have your boss contact me, I need a "parts" saw.

Steve

Yea right... with the way the state runs and its budget any $1000+ piece of equipment is going to be held onto come hell or high water. That of course means fix it and keep it running at the least possible expense. So I am going to follow Brad's and stihl038's advice as its the cheapest and then work up from there...

 

[TreeSurfer]

sounds like the same problem i had with my 394XP. when it dies, what side is it turned over on? my 394 has the tank vent on the clutch side and it dies when its up. i replaced the fuel tank and it was giving me the same issues so i dont think its the tank vent. sounds like its the crank gasket or a carb issue. most likely if the carb is clean its prolly the gasket but clean the carb first and then get a pressure test to make sure its not leaking.

 

[MEATSAW]

sounds like the same problem i had with my 394XP. when it dies, what side is it turned over on?

Clutch cover down, starter assembly up.

 

[stihl038x2]

Yea right... with the way the state runs and its budget any $1000+ piece of equipment is going to be held onto come hell or high water. That of course means fix it and keep it running at the least possible expense. So I am going to follow Brad's and stihl038's advice as its the cheapest and then work up from there...

Yeah, can't fault a guy for tryin' :tongue2:

My 088 was fixed in 10 minutes + $5.00

Steve

 

[MattCrowe]

I have checked out lots of P&Cs through the exhaust port and never seen it bubble around the rings...

You may have checked out lots, but this was obviously the first one you checked out that was full of fuel...

 

[MEATSAW]

You may have checked out lots, but this was obviously the first one you checked out that was full of fuel...

Touchè

 

[jus2fat]

Not to be rude...just gotta ask..??
Why are you posting in RED...It's hard / contrasting to my eyes..!!

A few words for emphasis...I understand...but the whole post = blaring imho..!!
Thanks...

J2F

 

[rmh3481]

Take a close look at the carb. The ethanol gas takes a toll on the diaphragms causing them to harden up much sooner than in the past. The metering diaphragm reacts to every breath the engine takes, and if the lever is sticking open it floods.