I own an older Shindaiwa string trimmer that I seem to have a problem getting gas up into the carb. It's an older model S20 (which I'm told is similar to the T20) with a TK carb. This model has the primer bulb (black) on the single fuel line in first picture. After pumping the primer bulb, I can feel the gas coming through the line and the trimmer will start up but only for one or two seconds (and best with full choke). I have removed the carb; it was clean but I installed a new kit with all new gaskets and diaphragms. This made no difference at all.
I next took off both the muffler and the air filter to make sure air flow isn't an issue and that made no difference. What I have learned is that I can repeatedly squeeze the primer bulb once every 2 or 3 seconds and the trimmer will run for as long as I want to do this (over a minute so ignition isn't the problem). When I pump the gas via the primer bulb, it runs with full power and throttle response. Last I removed the fuel line that goes from the carb through the grommet and down to the filter inside the tank; and it looks normal with no visible cracks that I could see. I'd replaced that fuel line and filter some years ago and it all looked in good shape.
So for some reason this TK carb still cannot pull the gas up into the carb. I've actually had the carb out three times now (taken out all screws and cleaned internal orifices) and still can't figure what else could be wrong. (I've looked carefully and there is no internal screen in this carb) Any ideas of what I'm missing or should try to do next would be helpful. Maybe replace the fuel line again even though it seemed normal ? ?
I next took off both the muffler and the air filter to make sure air flow isn't an issue and that made no difference. What I have learned is that I can repeatedly squeeze the primer bulb once every 2 or 3 seconds and the trimmer will run for as long as I want to do this (over a minute so ignition isn't the problem). When I pump the gas via the primer bulb, it runs with full power and throttle response. Last I removed the fuel line that goes from the carb through the grommet and down to the filter inside the tank; and it looks normal with no visible cracks that I could see. I'd replaced that fuel line and filter some years ago and it all looked in good shape.
So for some reason this TK carb still cannot pull the gas up into the carb. I've actually had the carb out three times now (taken out all screws and cleaned internal orifices) and still can't figure what else could be wrong. (I've looked carefully and there is no internal screen in this carb) Any ideas of what I'm missing or should try to do next would be helpful. Maybe replace the fuel line again even though it seemed normal ? ?
Last edited:
