I live down in wonderfull hot and humid houston also!!!! My Cobra is put on top of my 4 post storage until October. Way to HOT,HUMID,DAMP!!!!! I have a 25 year old mercruiser (GM engine) where the first
oil change occured 6 years after new because the
oil filter rusted through and filled the bilge with
oil LOL. Boat has been abused beyond reason, thermostat is 140F as is most seawater cooled engine to prevent salt from plating out. I purchased the boat in year 7 of it life. Boat sits 6 months out of year, has 2800 hrs on it and lives most of it running life at 4500 rpm. Besides using ether to get it started at times it runs perfect. I change the oil every 3 years because it a PIA. I did have the intake/exhaust manifold rott through once but that has nothing to do with oil, it did however cause the sump to fill up with 6 quarts of saltwater. That was 9 years ago. By the way it has points and condesor for ignition. I have been on many boats but I get the best buzz on mine, maybe it the ether I use to start it.