STIHL FS 45 Won't Start

[slomo]

Fuel out of the exhaust means the needle is sticking open. Do trimmers have a needle in the carb? They don't have float bowls like push mowers. Sounds like the engine is getting flooded out with excess fuel. As you can tell I'm no trimmer expert. There has to be something to meter the fuel into the carb. I'm sure a real expert will chime in here to help more.

One oil container per 2.5 gallons of gas sounds different but not impossible. Usually a 50:1 mix is 2.6 ounces of oil to 1 gallon of gas. Might check your oil mix again??

Might have a weak ignition coil or fouled plug??

slomo

 

[bertsmobile1]

Fuel out of the exhaust means the needle is sticking open. Do trimmers have a needle in the carb? They don't have float bowls like push mowers. Sounds like the engine is getting flooded out with excess fuel. As you can tell I'm no trimmer expert. There has to be something to meter the fuel into the carb. I'm sure a real expert will chime in here to help more.

One oil container per 2.5 gallons of gas sounds different but not impossible. Usually a 50:1 mix is 2.6 ounces of oil to 1 gallon of gas. Might check your oil mix again??

Might have a weak ignition coil or fouled plug??

slomo

YES.
Cube carbs have a needle
They work EXACTLY THE SAME as a float carb
The only difference is a float carb has a gravity bowl and a cube carb has a pressurised metering chamber.
Once you get your head around the metering chamber is the equivalent to the float chamber they become a lot less mysterious.

 

[amadago]

Thanks all for the help. I received my carb-kit today, and put it on. Within a couple of priming cycles, it started right up. Thanks for all the help - $16 bucks to get it back going is all it took.

 

[Fish]

Just go to the Stihl dealer and buy a new carb.....

4140 120 0610 CARBURETOR $34.50


4140 120 0619 Carburetor C1Q-S186 $34.50


4140 120 0621 Carburetor C1Q S216 $34.50


4140 120 0625 Carburetor C1Q-291A $34.50

 

[Fish]

OOoopps,
too late.....

 

[amadago]

So I guess I spoke too soon. It ran for a few min, and then it started getting bogged down when I pulled the trigger. Eventually it just shut off. It would start back up, then shut off, over and over. Since I bought a rebuild kit, I changed out the fuel filter, line and air filter to be sure it wasn't that, but it wasn't. Whenever I try to start it now, it starts up for a second and then backfires - which it never has done. Any thoughts on that?