I recently purchased a boat with a 2006 Optimax 115 with 230 hours on it. I bought it from a older gentleman that hasn’t run it for two years. Before the deal was finalized he took it to a dealer that replaced the impeller, a seal and the lower unit oil. They started the motor and confirmed that the computer showed no codes. I’m pretty sure the fuel filter and spark plugs have never been changed. I took the hose off the one end on the fuel box and drained some fuel into a glass, didn’t get much but I did get what I consider a lot of dirt for the amount of fuel. Is there a way to flush this out when I replace the fuel filter? What else should I do to this motor before I run it? Thanks!