I went to change the oil on my 90 yamaha after it had been sitting for a month. I pulled the filter and found it be dry, not a drop of oil in it.
Would this normal for a engine that has not ran for 30 days?
The 4 cylinder motors up through the 150 will drain back the oil from the filter and the oil galleries. The motors when started to take a short time to get oil into the chambers and to build up pressure. It is really bad for the motors to start them with the throttles advanced so the rev up high when they start without oil in the system passageways and filter.