by Miker » Tue Jul 26, 2016 7:59 am
Just a point on the difference between 2 and 4 stroke. Maintenance. Whilst the 2 stroke is more powerful and lighter for a given hp rating, it will use more fuel, and you will have to either pre-mix or keep the 2 stroke fuel tank full. 2 stoke motorcycles are harder to get passed for aust design rules because of their pollution rate compared to 4 stroke. The two main issues for maintenance issue on a 2 stoke is if you get your fuel mix wrong, and when the crank seals go. You'll know they're gone because oil will dribble down the leg. Keep 2 sets of plugs handy, you'll need them. Stinky, smokey and usually have a nice oil slick around them because the purpose of the 2 stoke oil is to lubricate and then get partially burnt on its way through. It doesn't all get burnt, it floats around in the water. Forget to mix your fuel and the engine is toast.
Whilst a 4 stroke for a given hp rating is a little heavier, (11kg for the 9.8) it is more efficient in fuel use and much easier to maintain. Mine is a 2004 model, I change the oil every 100 hours or so, or every two years. It can be done on the boat. Fuel filter and water pump only need servicing when they fail. Change plugs every 5 years or so. If you're worried about valves and camshafts, don't. They will only need attention if you run out of oil. the engine will run on unleaded, 85 and 98.
In know some people love 2 stokes, but in my opinion they're good on motorcycles, but on boats when you need to have a fail safe start, 4 stroke is a safer and more economical option in the long run.
Michael
"Dulcamara" - MKIII
Careel Bay, Pittwater
"Order of the Tipping Dinghy" 2017