I have a 1987 Merc Black Max and that I inherited from my father. It had been sitting for a year or so and the fuel gauge doesn't work very well and I recently ran it out of gas on idle. After I filled it back up I took it out and once at full power it keeps hitting short 5-10 second spots of losing RPM's and power then it kicks back up where it is supposed to be, runs great for 30 seconds or so and then another short dip in power. Seems like it's not getting fuel properly. I know nothing about outboards and what I've been told about this engine is to run it until it starts beeping and then bring it in. Could this be a simple fuel filter issue or does it need some fuel cleaner maybe?????