Stihl FS94 problems

Quackaddict

LawnSite Member
An ongoing thread, and I will also report that I had issues with a 2 week old FS94r. Bought a new trimmer to shed some weight from my KM110 and immediately it was acting up. Would not start, when it did it took forever to even get the head to spin, and then just general crummy operation from there. Sent it back to the dealer and its been there for going on 3 weeks now.
 

Integrity-LC

LawnSite Member
Location
West Michigan
Ill add to the 94 complaint pile. I LOVE how light it is, thats why I bought it but the dang thing is temperamental and kind of a turd. Last week I found out it will build up crazy pressure in the fuel tank if left under the bed cover of my truck and will not run until you crack the gas cap and let fuel explode all over the place. Ive had tons of handheld and small gas equipment that Ive never had to do that with. My 4 mix trimmer on the other hand starts fist pull every time and just runs. Im seriously thinking of selling it for a lightweight dedicated trimmer.
 

RussellB

LawnSite Fanatic
Wow. I'm surprised. I've had one for years and it was ran daily on HOAS for at least two years before I ran it out of gas and left it hanging in my enclosed trailer. Broke it out the other day, gassed it up and it fired right up. i forgot how light they are compared to other models. I like it.
 

ed2hess

LawnSite Fanatic
I have a lot of experience tuning carbs. My earlier post in this thread, I mentioned tuning them. The problem seems, when you tune them, at full warm up temp, at, say, 78 degrees ambient temp, then you go and try to run them at 95 degrees ambient temp, they won't run. I even tried backing out the HS screw almost until it fell out... Still not enough fuel. It's like the fuel was effervescing and causing an extreme lean condition. Either that, or the coils are effected by high ambient temps, I'm not sure. I just don't feel like these 94Rs should be unusable in hot weather, especially less than one season old. The 90Rs and 91Rs seem to hold a tune, and run no matter what. While I do like the power to weight ratio of the 94R, I'm regretting switching from the 90R/91R.
That carb design is bad.....
 

Jimbo45

LawnSite Member
Location
Illinois
Update. After the carb tune, new plugs, etc., I've used both 94Rs 3 times now, in 80 - 90 degree temp. No problems, they start easy and run fine. But, I guarantee, once temps get over 93 or 94 degrees, they won't run right, and won't rev up. I'll test my theory once we get those temps.....
 

Eagles71

LawnSite Member
Has any one had issues w choke “popping out”. The spring releases before you get it started in choke position. Had the 94 for month and a half.... nothing but issues.
 

Mumblingboutmowers

LawnSite Senior Member
Update. After the carb tune, new plugs, etc., I've used both 94Rs 3 times now, in 80 - 90 degree temp. No problems, they start easy and run fine. But, I guarantee, once temps get over 93 or 94 degrees, they won't run right, and won't rev up. I'll test my theory once we get those temps.....
I assume that you are most likely correction in your theory. I have the same troubles with Stihl. Try this, keep the head out of the sun when it is sitting in the truck or on the trailer. It seems to me that it is the "sitting directly in the sun" that causes these problems the worst. I started sliding the head under my toolbox to keep it out of direct sun when I am mowing. It has really seemed to make a big difference.
 

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