May be kind of obvious but are you leaving it tilted up when hosing it down or while stored?
Also, I've noticed on mine when I hook a hose up to the hose connection to flush, I can get drips from the 'tee' connection inside the cowling, this is the 'tee' located where the line to the tell-tale is connected. These are just push-on fitted. If you have only a little bit of water accumulating, I'd look at this.