I recently purchased a Jon boat with a Mariner 30hp (Model# 30AE689 401221). After having the carbs cleaned at the local outboard shop, due to stitting for just short of a year, it still will only run up to half throttle. After half throttle it just bogs down. Tried changing the prop to a lower pitch but it made no difference. Old owner said it ran fine when he quit using it but I still changed out gas, tank, fuel lines, and filter. Starts, idles, and runs good up to about 2000 rpm. I need ideas what to try next. The mechanic told me this model was actually a "yamaha version" if this helps.
