Stihl FS94R hard start. Ideas before carb replacement?

[brokeasajoke]

So as the title says, I have a roughly 3 year old FS94R stihl 2stroke trimmer that all of a sudden became troublesome to start. A touch of anything flammable on the air filter and it will fire right up and continue to start well warm, with one pull. Trimmer runs great once running. Just a starting problem not a running problem. I pulled the carb apart with the exception of the jet screws and cleaned it. Sounds like low compression problem but the age of the trimmer makes me raise an eyebrow to low compression. I've never run it without an air filter and always use ethanol free gas always mixed 50:1 or high 40s:1. My compression gauge has seem to went on a vacation somewhere. Up for any ideas before I drop $60 on a new carb which I don't care to do if I know it would solve the problem. Thanks.

 

[Roadworthy]

If you've not already done so you could try replacing the fuel filter. It's inside the tank and accessed by pulling that big rubber plug where the fuel line exits the tank.

 

[brokeasajoke]

Carb has the bubble and primes well for what ever that's worth.

 

[newbury]

Try running something like Seafoam through it.

 

[brokeasajoke]

Local dealer has carbs for 44.99 plus tax so I ordered one.

 

[xrjohndeere]

So as the title says, I have a roughly 3 year old FS94R stihl 2stroke trimmer that all of a sudden became troublesome to start. A touch of anything flammable on the air filter and it will fire right up and continue to start well warm, with one pull. Trimmer runs great once running. Just a starting problem not a running problem. I pulled the carb apart with the exception of the jet screws and cleaned it. Sounds like low compression problem but the age of the trimmer makes me raise an eyebrow to low compression. I've never run it without an air filter and always use ethanol free gas always mixed 50:1 or high 40s:1. My compression gauge has seem to went on a vacation somewhere. Up for any ideas before I drop $60 on a new carb which I don't care to do if I know it would solve the problem. Thanks.

Take the carb apart and see if there is a gunky film on the inside? You can scrape it and it looks like plastic. I had a Stihl weed eater that I had the dealer repair the carb every year because of the exact symptoms. He took the carb apart and showed me this film. He said it was a common problem. Something they put on the aluminum during manufacturing in China. It comes loose and plugs up the jets.

 

[jaxs]

Let us know if new carb solve's the problem.
On a side note. When I bought my Husqvarna trimmer and saw they offered additional 3 years warranty if I bought 3 quarts of their pre-mix for each. I continued using pre-mix and both started and ran perfect for over 4 years,,,,,,then my son borrowed the saw. After I went to his house and retrieved it,the engine bogged each time throttle was pressed. True to their promise,the dealer fixed it under warranty. The tech told me the carb looked to had poor fuel ran through it and said he woudn't run pump gas if it was free. I realize this debate has gone on for years but I look at it like this. If mfgr is that generous with warranty and confident enough a consumer will be convinced and continue after using 3 quarts,they should know better than shade trees.

 

[brokeasajoke]

Take the carb apart and see if there is a gunky film on the inside? You can scrape it and it looks like plastic. I had a Stihl weed eater that I had the dealer repair the carb every year because of the exact symptoms. He took the carb apart and showed me this film. He said it was a common problem. Something they put on the aluminum during manufacturing in China. It comes loose and plugs up

Let us know if new carb solve's the problem.
On a side note. When I bought my Husqvarna trimmer and saw they offered additional 3 years warranty if I bought 3 quarts of their pre-mix for each. I continued using pre-mix and both started and ran perfect for over 4 years,,,,,,then my son borrowed the saw. After I went to his house and retrieved it,the engine bogged each time throttle was pressed. True to their promise,the dealer fixed it under warranty. The tech told me the carb looked to had poor fuel ran through it and said he woudn't run pump gas if it was free. I realize this debate has gone on for years but I look at it like this. If mfgr is that generous with warranty and confident enough a consumer will be convinced and continue after using 3 quarts,they should know better than shade trees.

I took the carb apart and cleaned wit brake cleaner and sprayed all holes. I always run ethanol free fuel and clear out the gas nozzle hose into truck or mower first. Always use stihl ultra silver bottle. Once it starts it runs great.

 

[xrjohndeere]

I took the carb apart and cleaned wit brake cleaner and sprayed all holes. I always run ethanol free fuel and clear out the gas nozzle hose into truck or mower first. Always use stihl ultra silver bottle. Once it starts it runs great.

That is exactly how mine was. I ended up replacing the carb with a new one and that I believe fixed it. I was so ticked off at it I gave it to my nephew. He said it starts and runs like a champ. Go figure. I went and bought a 4 cycle Husqvarna. No mix gas. Starts very easy and quiet. I also have a Ego battery powered weed eater. I like it better than any others I have had. Squeeze the trigger and go. Good luck. It can be frustrating.

 

[brokeasajoke]

New carb new plug same symptom. Carb was pretty well set from the factory though. Idles good and seemd to be about right wide open. Had to give it a snuff of brake cleaner to get it going though just like before.