My trimmer runs great-on half choke

[Fuzly]

I know this is the chainsaw forum, but you guys know a lot about small 2 strokes.

I have a Stihl FS45 trimmer that runs great, if I leave it on half choke. It had some lag in acceleration. I backed the low screw out and it helped with the lag. I kept backing it out, and nothing changed.

Is it not getting enough fuel? I just got it last year at this time. It took a long time to warm up last year, but was fine after that-ran fine with the choke off.

Starts easy, wacks the weeds, but if I turn the choke all the way off it dies immediately.

Thanks in advance

 

[belgian]

I am not Lakeside ( ) but gonna try anyway :

looks like your saw is leaning out fast. I suspect the following :

- clogged air filter (check if is real dirty)
- carb cleaning (idle jet or mesh screen could be clogged with dirt)
- worst case : air leak, but with a one year old model, quite unlikely.

Lake, whadja think ....?umpkin2: umpkin2:

 

[Fish]

Take the carb apart and clean it out, make sure you remove the needle
and clean that passage too, and visually verify that it is clear by holding it
up to the light. Inspect the fuel line for cracks, Stihl had a problem a few
years back. If your fuel line is green, it should be OK. Reassemble, and try some fresh fuel mix, and you should be ok.

 

[Lakeside53]

Belgian: good try, but blocked air filter makes it run rich...



Fish - correct! but... had two machines in this week where the GREEN fuel hose has gone to crap (brittle, disintegrating) and the carb was full of the greenies... bad... and I too thought the green hoses were good.


Do check your fuel filter (replace it anyhow).

 

[Fish]

I have not seen a bad green one yet, but thanks for the heads up.
The green ones are still 1000% better than the old black ones.
That old/bad fuel excuse was kind of hard to use after a while.
Especially when the guy's old 031 was still using the original fuel line.........

It took Stihl a while to finally admit that there was a problem .
Same with echo a few years later.

 

[RIX]

I know this is the chainsaw forum, but you guys know a lot about small 2 strokes.

I have a Stihl FS45 trimmer that runs great, if I leave it on half choke. It had some lag in acceleration. I backed the low screw out and it helped with the lag. I kept backing it out, and nothing changed.

Is it not getting enough fuel? I just got it last year at this time. It took a long time to warm up last year, but was fine after that-ran fine with the choke off.

Starts easy, wacks the weeds, but if I turn the choke all the way off it dies immediately.

Thanks in advance

That is pretty strange man, I have the same trimmer, that I bought last July and it is doing the exact same thing, I have the green fuel lines as well, I guess I have some work to do as well. Thanks Guys. :biggrinbounce2:

 

[Lakeside53]

I doubt the fuel line is bad after only year. The cause is often the L internal jet and/or check valve. The problem is usually from leaving gas in them over the winter. The L fixed jet is tiny... you'll need an otoscope or strong magnifier to see an issue. Try spraying it out with carb cleaner, and let it sit for a while in a jar of straight gas.

 

[RIX]

I doubt the fuel line is bad after only year. The cause is often the L internal jet and/or check valve. The problem is usually from leaving gas in them over the winter. The L fixed jet is tiny... you'll need an otoscope or strong magnifier to see an issue. Try spraying it out with carb cleaner, and let it sit for a while in a jar of straight gas.

Thanks Lake
Fuzly, I don't know about yours but for mine I have run at least 1.5 full tanks through it this season before it started doing this just last week, the gas is maybe a month old and i did put some sea foam in it the day I got it. Pretty strange I think but I'm sure no know it all on this stuff.

 

[Fuzly]

Do check your fuel filter (replace it anyhow).-The problem is usually from leaving gas in them over the winter.

Lake, thanks much. The fuel filter is the first thing I will do. Is it hard to get at? I doesn't look like I can fish it out easy with a hook like on the saws.

And yes, I'm ashamed to admit I left gas in it over the winter. I thought for sure I dumped it out of the trimmer into the ice auger and ran it dry-but I thunk wrong. Now I get to take a tiny carb apart.

 

[Fuzly]

Thanks Lake
Fuzly, I don't know about yours but for mine I have run at least 1.5 full tanks through it this season before it started doing this just last week, the gas is maybe a month old and i did put some sea foam in it the day I got it. Pretty strange I think but I'm sure no know it all on this stuff.

Me neither, that's why I'm here.

I'm getting paranoid about gas mix now. I got a ratio-rite pitcher and am only mixing 1/2 to 1 gal at a time.

I have to admit I was kind of ticked off at first. This thing is barely a year old and my Stihl guy (who is great by the way and who will get the trimmer if I can't fix it) gave me the "don't buy from x-mart, Stihl is way better" speech. But, I NEVER leave gas in stuff over a few months (intentionally). I can understand by the size of the carb on the outside that the jet is tiny. And, in the words of my Suzuki dealer "today's gas it total s..t, don't leave it in anything if you can help it"

 

[belgian]

Belgian: good try, but blocked air filter makes it run rich...

:blush: :blush: :blush:

 

[Stumpcutter1]

bet shes gummed up pull the needle clean it out I'll bet she runs fine

 

[Fish]

wow





















































































































































I do not exist.................................................................

 

[Stumpcutter1]

wow





















































































































































I do not exist.................................................................

thats alot of space,lol

 

[Fish]

my non existence takes some space,..................................

 

[Lakeside53]

 

[Just Mow]

Where is FISH
Has anybody heard from him

 

[rreidnauer]

Where is FISH
Has anybody heard from him

He was last seen sleeping on his enter key. :biggrinbounce2:

 

[Fuzly]

Fish - correct! but... had two machines in this week where the GREEN fuel hose has gone to crap (brittle, disintegrating) and the carb was full of the greenies... bad... and I too thought the green hoses were good.

See, you do exist!:jester:

Thanks everybody, especially Fish. It's going to be a few days before I can get at it, I'm working 12s and don't feel like it when I get home.

If memory serves, my lines are black.

 

[Simonizer]

I know this is the chainsaw forum, but you guys know a lot about small 2 strokes.

I have a Stihl FS45 trimmer that runs great, if I leave it on half choke. It had some lag in acceleration. I backed the low screw out and it helped with the lag. I kept backing it out, and nothing changed.

Is it not getting enough fuel? I just got it last year at this time. It took a long time to warm up last year, but was fine after that-ran fine with the choke off.

Starts easy, wacks the weeds, but if I turn the choke all the way off it dies immediately.

Thanks in advance

Dump the fuel, add clean, fresh fuel mix. Install a carb-kit, your metering diaphragm has gone stiff from stale fuel. I can't remember but I think the kit is a Zama RB-66. Should be about $16.00. Like the other fellows said, check/replace fuel lines. Bosch WSR6F spark plug doesn't hurt either while your at it. Cheers.