I'm on my 6th or 7th year with this saw, no issues until recently. I have a saw box I store it in and have noticed it was leaked bar oil. And the saw vents for air are gummed up, oily saw dust. There is an adjustment screw for the bar oil output, but it only turns about 1/4 turn. It has a stop going right and a stop going left, 1/4 turn. Is this correct? Seems odd a pump output adjustment would be as limited as that. Anyone familiar with this?