I am the third owner of an '85 O'Day 26 with an 8 HP Yanmar diesel one-banger and Edson wheel steering. Due to recent double-knee surgery, I cannot easily get down into the engine compartment to find the engine model, but I assume it is a 1GM10. Is there a brand of oil filter that can be purchased from an auto parts store or do I need to buy a specific Yanmar spin-on filter? There is a lot of play in the steering wheel due, in part, to worn fittings on the rudder. Any suggestions? For those who have marine heads, where is the sea cock for flushing water? If the toilet were to get stopped up, will a plunger usually work or do you have to take the flushing line to the holding tank apart(I have not used it yet?) How do you sanitize the fresh water system so that it can be used for other than just washing your hands? All this seems to be inherent with buying a previously owned boat that is no longer manufactured.