I have a BC1600 that supports multiple attachments. I've been using it for a little over 2 years now. While I was using it the other day, the engine started dying down/revving up when I squeeze the throttle. The engine starts and idles fine.
Whenever I hold down the throttle, the engine will die down then rev back up repeatedly. It enver cuts off, but as soon as it gets to the max RPM, it slows down, then goes back up. There isn't an abnormal amount of smoke coming from the trimmer. I replaced the spark plug and that didn't help. The old one was pretty fouled up. The manual said to adjust one of two plastic screws located near the fuel intake, but it was already in the fully adjusted position.
I used the proper oil/gas mixture on the last batch of fuel.
Any ideas on what could be causing this ?