Stihl FS 130 - 4 cycle trimmer

[RCW]

Stihl FS 130 - one of the larger Stihl trimmers, 4 cycle, with bicycle bars and grass head. Grass head is the kind you cut the line to length, and stick in the head. 4 years old, bought new. Probably gets 40 hours of use per year.

Couple times a season, the carburetor will load up, runs rich to the point of soaking the air filter with gas/oil, then it chokes the engine out. Has happened since new, and only once in a while. Smells rich while its running.

Put in clean filter, runs like a top. I keep 3 filters around - clean them with dish soap.

I mow some heavy stuff, and often will put line in a little long. Sometimes RPM's aren't WOT, but get there when line wears down.

I have heard it can be caused due to siphoning/drawing excess gas after exhaust stroke, but haven't found anything reliable. Friend of mine owns the dealership. They never heard of it. Wouldn't have that issue with a 2 cycle engine, and I have a 25 year old 2 cycle FS 86 that has never had a similar problem. (Ethanol gas beat that up)

Anybody run across similar issue? There are a lot of these Stihl 4 cycles out there now....Sorry so long, just trying to get all the details in.

It's easily manageable; just bugs me......

 

[hodge]

I have an FS130, and it has run flawless. I've got a friend with one, too. He's had no issues.
I've not read of this being a problem with the 4Mix, so I'd say you have a unique issue. Are you running ethanol gas through it? I, and my friend, both have access to ethanol-free gas, and use it. I doubt that this is the difference, but ethanol can do goofy and nasty things to carburetors.

I love the 130, and would buy another one in a heartbeat.

 

[RCW]

Are you running ethanol gas through it? I, and my friend, both have access to ethanol-free gas, and use it.

Thanks, Hodge. I really like my 130, too. Just an odd problem. You can wring the gas and oil out of the filter when it happens.

Ethanol-free has been available since I bought this one. I always use ethanol-free for all small engines. Also, Stihl recommends synthetic 2-cycle oil, which I use for all of them.

A friend that owned a tree service for many years has one, and he's the one that told me about the siphoning thing. He's pretty good with saws, etc. He didn't have an problem with his, either. Just told me that after I explained my problem to him.

 

[RCW]

Here's a picture of the last filter after I pulled it. Put in paper towel and stood on it to squeeze out gas/oil.

Gas has vaporized, but I hope you can see how much oil came out.

Like I said, only happens once in a while......

Our boxer is concerned!

 

[Tooljunkie]

Carburetor adjustment may play some part in this. And habit as well. Those machines like to run wide open. A little rich and it takes a little longer to reach max rpms. The pcv (if i recall it has) will slobber the rich mixture backto the filter.

Wide open throttle, lean out to max rpms then 1/2 turn rich. Also make sure cable is pulling to wot, it has adjustment as well.

The fs130's i looked after had over 1000 hours each on them. Biggest thing, dont drag trimmer head on ground and grease gear head bearing often.

 

[Diydave]

Haven't had a bit of carb trouble, with my 130, since I changed all 2 stroke base gas, to VM&P NAPTHA (AKA, Coleman stove fuel). Before that 2 years was max life for ethanol riddled carbs...

It may seem expensive, to use $13-14 dollar fuel, but price a carb installed by the dealer (I don't do 'em any more, bad middle aged eyes).

IMHO, it is a foolish economy, to use today's crap gas, in any 2 stroke engine...

 

[Tooljunkie]

I solved my middle age eye trouble with a big magnifier with a light. Its loke a desk lamp,placed near my bench grinder to see while sharpening drill bits.

Havent used white gas in any internal combustion engine. Never crossed my mind to use it. I add sea foam to all my mixed gas

 

[RCW]

Thanks for the suggestions, guys.

I think Frank is onto something; going to try some carb adjustments. Honestly, didn't tinker with it, since it seemed sporadic.

Will let you know how I make out.

 

[William1]

I too, have a 4Mix (combi 110) Stihl. Just bought a Stihl chainsaw (little MS193 with a 14" bar for limbing) today. Dealer explained the carb is supposed to return excess fuel to the tank. So when priming for example, you cannot flood the engine, it just fills the carb and the excess, back to the tank. Vacuum allows fuel in. If yours is not returning excess fuel, I'd look for a clogged or stuck check valve.

BTW, I use the Stihl 'MotoFuel' at eight bucks a quart. Two year life in the machine, ten years if the can is not opened. I use only two cans a year so I see it as cheap insurance. If I went thrugh gallons of fuel, I'd use regular premix but the Combi might sit for (hopefully) six months sometimes. I'll probably use the 'Motofuel' in the new saw too as it will get (hopefully) minimal use though if I have a lot to do, I'll run regular premix and at the end of the day, drain the tank, fill with 'Motofuel' and run for five minutes.

 

[alansz400]

If you have not checked the valve clearance I would pull the valve cover off and do that. Might have a intake valve that is not shutting all the way and letting the oil and gas mix get blew back into the air filter.

 

[Saxman]

I agree on checking the valve clearance and use only Stihl full synthetic oil mix in the highest octane gas you can buy.


Steve

Lincoln SA200 (1966 Redface)
Lincoln IdealArc 250

 

[RonBoyBX25D]

I would try the Stihl or an alternate pre-mix fuel that is high octane & no alcohol. I have all Echo and use their version, the dealer told me it was pretty much all the same. Since I started using it my trimmer runs like new and is nearly 20 years old.

 

[Tooljunkie]

Im considering the premix myself. Curious to see how it does.valve clearance may be possible, but unlikely. Open valve =no compression. Unless its just a little tight. But issue would be a continous problem. On that note so would be carb adjustment.
My trimmer loads up like crazy when i tap to extend cutting line.takes a few seconds to cut line, longer when i run the heavier stuff.

 

[RCW]

Guys - just wanted to get back on the trimmer.

Like I said, I think Frank was on to it.

This trimmer has always had 91 octane ethanol-free, and Stihl synthetic oil.

Throttle cable linkeage is good. Did NOT play with carb yet, wanted to try some other stuff first. Have also not checked valves, for same reason as the carb. Gear box is always greased well.

My first post with the question said this trimmer has the type of string head that you cut the line to length, not the windy-spool thing. It came with the spool thingy, and damn thing always gummed up with 0.105" line I use. Went back to the tried-and-true single-use type first season.

I believe what was happening is that when I load string, I tend to make it too long. If I'm in heavy stuff with long line, RPM's drag. If I'm in it long enough, she starts to load up. I don't think its an issue if the line is long doing basic trimming - not enough load to pull RPM down. Did the same thing with my 25 year old 2-cycle Stihl FS 86 for many years without issue. Like Frank said, problem could just be a matter of habit.

It hasn't failed in a month, but I haven't gotten into real heavy stuff again. Been keeping line a little shorter - seems good to go!

Will be interested how it runs next time I'm in heavy stuff for an hour or so steady.

Thanks again! You guys are great.

 

[Tooljunkie]

I bought some husqvarna premix. I like. Starts easy, virtually no smoke.revs up better.
May have to try it in my gasbike(grubee 50cc kit on my mountain bike)
And on that note, pull muffler and clean spark arrestor screen. If you like to use synthetic oil and mix a little rich to be on the safe side that would explain a power loss. It compounds, plugged screen, more throttle more fuel less power. Soots up screen quick.
Add a little sea foam to all your mixed gas.stabilizer as well as cleaning agents. I use it in all my yard power products.

Oh, when running on the premix fuel, it smells nothing like gasoline, more like a coleman stove. Just sayin.

 

[RCW]

If I remember correctly, I threw the screen out a couple years ago when the trimmer fouled up. Spark arresters aren't usually important in upstate New York.

I looked at the canned stuff couple times recently. I use ~ 4 or 5 gallons per year. Would take almost whole can to fill the Stihl 046 Magnum chainsaw - seems like tank is 0.7 liter.

Been dosing the gas with StarTron, but also have Seafoam.

 

[Tooljunkie]

carbs usually don't really foul up, but adjustments are necessary. One is cable adjustment for wide open throttle, other 2 are high and low rpm mixture. Oh, fourth is idle stop screw. I set cable so it pulls wide open, then back it off a touch so trigger bottoms out in handle and not in carb.
Then set idle mixture for max rpms and back down idle stop til trimmer head stops. Then adjust high rpm for max revs and then a touch rich.
A couple rounds of adjusting and throttle cycles and it's good to go.

 

[RCW]

carbs usually don't really foul up.

True, guess my poor explanation.

Still thinking if I run line too long, coupled with real heavy weeds/brush, it runs rich, and fouls the filter. The filter is the issue, and I'm thinking caused by reduced RPM in heavy weeds, trying to use too long a line.

I do quite a swath of border to the woods a couple times a year, and sometimes I'm knocking down goldenrod, etc. 3 or 4 foot tall. Fresh honeysuckle, sumac, box elder, often in there too.

As I think about it, its usually when I'm in the heavier stuff I have problems. Again, has only been an issue 4 or 5 times in 4 years.

I used to use the nylon blades on the head, but they tend to get locked back into the head if they hit something hard.

Maybe I just need to break out the old FS 86 with the steel blade on it for the heavier stuff.

But again, so far, so good.

But Frank, I will keep your wise advice in mind if this doesn't work. Thanks again.

 

[Diydave]

Definitely, don't use too long a line. Can also put adverse wear, on the centrifugal clutch...

 

[RCW]

Definitely, don't use too long a line.

Yeah, thanks Dave. I really am beginning to think its more a matter of how I always did stuff.

The FS 86 got hit by the ethanol gas, but after a couple carb teardowns, it runs pretty decent. At 25 years old, its been a great machine. Like I said, keep a nasty 3-point brush blade on it.

In recent years I've been able to get the e-free stuff at 2 local gas stations, and they sell a lot of it.

Thankfully, my 046 Magnum was never impacted by the ethanol. It's one thing to spend $400 to replace an old trimmer. A whole 'nother thing to replace a $1,100 chainsaw! 'Course, that'd be worth a new carb.