I am doing an entire tune up on my 2008 15hp Suzuki [DF15]. I would like your opinions on the following; -Best gear oil and weight? -Best motor oil and filter? -Best motor oil weight? -Best Spark plugs? -Should I replace my water pump with the OEM? -Best fuel filter? I can't find a good service manual for this thing, other than a parts catalog. All of your help will be greatly appreciated.