Hi Folks,
My first post. I have a 4 cycle model 990r Ryobi brush cutter/trimmer. It's about 15 years old, it is and has been a good piece of equipment. It is a split shaft that will accept attachments. I would like to use a pole saw attachment on it. My question is a 4 cycle engine (Ryobi)designed to be used in the up position that is required to trim limbs. In other word will the internals get oiled in this position. Thanks,

Kurf

You should be able to run the engine in all positions, but you might not want to run it continuously for extended periods. A few minutes at a time should be just fine.