018 Stihl fuel delivery(?) problem

[Jstpssng]

I bought this saw used from a dealer in Dec. As is,
but they are checked out before he puts them on the rack. It works great for cutting small trees on the thinning project I'm working on and for occasionally brushing out a property line; but when I turn it up to cut, as you would on a firewood pile, it bogs, sputters, and almost dies until the RPMs pick up again and it sort odf runs. I took it back and they did a spark test, compression test, and checked the fuel lines and filter. Their "repair" was to place a nut on the fuel line to hold it at the bottom of the tank... can you say "M-i-c-k-e-y..."
It seems to bother more with a full tank of gas; but loosening the cap to vent the tank doesn't make a difference. I've also cleaned the air filter.

I've got about $160 tied up in a $200 saw... I really don't want to go overboard. On the other hand it is a sweet little saw for what I uae it for, and between my thinning project and my real job the saw must have 80 hours on it since Dec.

 

[stihlman]

The MS179-180 saws seem to have that issue. I had a buddy's 170 all apart with the same issue. I fixed it but I did so many things to it I don't remember what I actually did to fix it. In the small Stihl saws the MS211 is my pick, I just got one myself and it has been great so far


Steve

 

[Jstpssng]

The MS179-180 saws seem to have that issue. I had a buddy's 170 all apart with the same issue. I fixed it but I did so many things to it I don't remember what I actually did to fix it. In the small Stihl saws the MS211 is my pick, I just got one myself and it has been great so far


Steve

I was afraid somebody would say that. When I dropped the saw off they said 'we just got a new one in with the same complaint."
In the last 30 years I've run an 015 and an 02? and they all seemed to have carb problems... guess I'll just have to suck It up.

 

[LD1]

Assuming this is the older 018 and not the MS180, I'd start by replacing the fuel lines.

The fuel lines in older saws dont like new ethanol gas. They get really mushy and they may "appear" to be okay, but could be collapsing when running.

Cant say for sure if this is the problem, but unless you are 100% positive you are running gas with no ethanol, if the lines arent an issue now, they will be later. So the few $$$ to throw lines one it isnt really wasted money even if it doesnt fix the issue.

But it also sounds like it could be a carb tune issue. Like maybe too rich and loading up????

I dont know so take my advise with a grain of salt. If this is indeed an inherent issue with the 018, you might just have to live with it.

 

[arrow]

Recently and about a hundred other times I had a problem like this with any brand of saw. It would run fine with the choke slightly out and not respond to throttle when pushed. LD1 gives sage advice. Fuel lines get encrusted inside as well as becoming microscopically porous after ethanol attack. This inside "varnish" can break off at times and plug the carburetor. If one is not used to doing it, fuel line replacement can be a pain and thus avoided even by a "shop". Solutions were either a carb rebuild, replacement or complete cleaning of the fuel system. When my saws got old after a couple three years as I used my saws heavily everyday, it had more to do with compression. Easiest thing to do first if you had not done so or if you know it had been done, is adjust for throttle response with the carb screw. Sometimes an overly lean set can also do this. Your "low speed" screw will adjust throttle response as well as it is not just for idling as some think. You have either a fuel path air leak or blockage problem.

 

[stihlman]

I am sorry I misread the original post. I have no experience with a 018. It is an older saw and the fuel line and carb would be the place to start. The small saws and their small carbs can't handle any debris in them.

Steve

 

[Jstpssng]

Well thanks guys, I now know where to start. I had forgotten that the exterior of the lines are no indication of how good they look inside. Cheap fix too, although a bit of a PITA

will follow through and report back.

:thumbsup:

 

[LD1]

Cheap fix too, although a bit of a PITA

will follow through and report back.

:thumbsup:

Good luck. Because they are indeed a PITA.

 

[arrow]

Good luck. Because they are indeed a PITA.

These Stihls have a molded and formed fuel line that just fits up to carb and tank. They do not create the frustrations that some chainsaw fuel line replacements can cause but it is best to remove the fuel tank to do it and some shops just won't bother..

 

[Fixemall]

The factory fuel filter for those saws is actually weighted to keep it in the fuel.
I agree that new lines and a proper filter are the place to start.