Catigale
think you will find in a modern, direct inject 2 stroke the cost for oil consumed is less than a four stroke oil change...especially if you consider changing the oil 4 times in one season because of dunking your engine....
Ha! Ha! You made me laugh. Well, I don’t plan dunking my engine (smile) and it has never happened so far (smile), and I hope it never does. But, seriously, based on 100 hours of operation which is when I need to make an oil change on my 4-stroke, when I asked around in my marina, the two stroke guys gave me figures of consumption that surprised me. Admittedly, it depends on how you use your motor (if you are using the higher rpm range most of the time or the lower range) and of course the price of 2-stroke oil in your area vs the price of 4-stroke oil. I do not have the exact figures at hand but I recall that my calculations at the time had presented a number not at all insignificant, to be taken into consideration when assessing the overall fuel consumption of a 2-stroke. With pricing of oil in your part of the world and how you use your motor I can see how this picture could be very different in your case. Thank you for your input.
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Bob
1. I agree with you totally on this point but I have solved this problem by having detachable steering on my motor. When I sail the motor stays centrally locked in the centre position and the rudder steering operates independently. In this position the motor swings up and down (in and out of the water) so that if while under sail, in an emergency, I need to use the engine it can be deployed very fast. When motoring in this mode, steering comes from the rudders only, which is fine on open water. When I come back into the marina I reconnect the motor to the steering for enhanced maneuverability.
2. You know Bob, I can’t really agree with you on this point, because if you are maneuvering in a marina you will be doing so at very low speeds in displacement mode (the hole shot performance relates to transitioning from displacement mode to planning mode). So slamming into reverse to avoid a collision at slow speed will produce a very rapid result regardless of your engine type or size in my opinion. Indubitably one needs to know and feel the ability and limitations of one’s engine and use it appropriately.
3. I think I’ve covered that with my response to Catigale.
4. If you had a higher gear ratio with a given 2-stroke you would, in theory, be able to swing a larger and/or higher pitched propeller that would most probably give higher speeds. But the lack of engine volume would probably allow that to work only on very light planing boats. This is how I see it but I may be wrong. I also think the gain in drag, if any, would be insignificant and should not be a determining factor in engine choice for our ‘slow’ speed Macs.
5. Do you have wedges on your E-tec 60? And at what angle?
In my discussions, when I refer to 2-strokes, I think only of the modern fuel injected motors.
You are right about wondering how reliable the new generation 4s will be – what with DOHCs and so many valves, it does set you thinking . . . .! However, there doesn’t seem to be anything negative in the air so far.
Thank you for your input Bob.
Octaman
sits mid-way between the port rudder and the engine. Hope this helps. The E-tec 75 is not much wider than the 60 but I don't have the measurements.
90HP looks scary fast 
