This is great. One guy says he's not taking the bait, even though he just did, and another has an engine that puts money in his wallet. Gotta get me one of those!
Quote from: "Boatdood"This is great. One guy says he's not taking the bait, even though he just did, and another has an engine that puts money in his wallet. Gotta get me one of those!You are absolutely right; I did take the bait. Did you intend to make a point of this or just start a little firestorm? You have had 17 posts since 2009 so you must have been helping out someother forum that I'm sure misses you by now...
Well there you have it.I should have guessed that Boatdood's demeanor was similar to mine.
I have owned both. I have ridden on many more of both of all brands including a buddy that re-powered with twin eTec 130's last year. If I were re-powering my decision would be based on the best deal and warranty. For the time being my old '97 Yamaha will have to do.
For the sake of discussion though, a few two stroke facts:Two strokes have a rapid wear zone in their cylinders. Two stroke pistons run hotter. Conventional two strokes are gasoline cooled. Two strokes actually do have an intake and exhaust cycle. Two strokes do have valves. And, two stroke outboards have more moving parts than a four stroke. Figure that one out.
What is better?, outboards are like boats there is no perfect one for every situation, its all about compromise and trade off's. No matter what you chose run it till the warranty is up and get rid of them as quick as possible and hopefully to someone you don't know.Capt Matt
Quote from: "Boatdood"For the sake of discussion though, a few two stroke facts:Two strokes have a rapid wear zone in their cylinders. Two stroke pistons run hotter. Conventional two strokes are gasoline cooled. Two strokes actually do have an intake and exhaust cycle. Two strokes do have valves. And, two stroke outboards have more moving parts than a four stroke. Figure that one out.OK, time for a fact-check:Wear zones - depends on cylinder base material, rings, and piston material and clearances. Remember Detroit Diesel truck engines are 2 strokes and seem to run a really long time... Runs hotter - depends on piston cooling and compression ratio. High compression engines have higher piston temps, but usually have oil jet cooling on the bottom face of the piston. 4 strokes are normally higher compression than 2 strokes, but 2 strokes fire twice as often. Two strokes are gasoline cooled - then why do you need a water pump? Sorry, this one does not pass the snicker test.Two strokes have an intake and exhaust cycle - so do rotary engines, miller cycle engines, and every other gas powered engine - cuz you gotta bring the air in a force it out. But the intake and exhaust in a 2 stroke happen in the same turn of the engine and the cylinder fires on every RPM. Four strokes (Otto cycle) fire every other RPM. Two strokes have valves - yes, they have reed valves to prevent back-feed into the crankcase. These are passive valves, not articulated by a camshaft.
Quote from: "GoneFission"Quote from: "Boatdood"For the sake of discussion though, a few two stroke facts:Two strokes have a rapid wear zone in their cylinders. Two stroke pistons run hotter. Conventional two strokes are gasoline cooled. Two strokes actually do have an intake and exhaust cycle. Two strokes do have valves. And, two stroke outboards have more moving parts than a four stroke. Figure that one out.OK, time for a fact-check:Wear zones - depends on cylinder base material, rings, and piston material and clearances. Remember Detroit Diesel truck engines are 2 strokes and seem to run a really long time... Runs hotter - depends on piston cooling and compression ratio. High compression engines have higher piston temps, but usually have oil jet cooling on the bottom face of the piston. 4 strokes are normally higher compression than 2 strokes, but 2 strokes fire twice as often. Two strokes are gasoline cooled - then why do you need a water pump? Sorry, this one does not pass the snicker test.Two strokes have an intake and exhaust cycle - so do rotary engines, miller cycle engines, and every other gas powered engine - cuz you gotta bring the air in a force it out. But the intake and exhaust in a 2 stroke happen in the same turn of the engine and the cylinder fires on every RPM. Four strokes (Otto cycle) fire every other RPM. Two strokes have valves - yes, they have reed valves to prevent back-feed into the crankcase. These are passive valves, not articulated by a camshaft.Time for a check of the facts in the fact check. Wear zones. So did you support or deny that fact? It's not really clear. Pistons run hotter. Again not really sure from your response. Keep in mind we are talking about outboard engines here. Conventional two strokes are gasoline cooled. I'm not sure what a snicker test is but notice that I did not exclude the water pump or the water cooling, only stating that they are gasoline cooled. If you deny that they are I'd like to hear a good reason for discussion. Two strokes have an intake and exhaust cycle. I see you agree with me on this one. Two strokes have valves. I see you agree with me on this one as well. I'm not sure what a passive valve is as opposed to an active one, or what you mean by articulated, but we agree on the valves issue. I've often heard it claimed that they do not have them which is why I brought it up. Two strokes have more moving parts. I see you steered clear of that one. Seriously there is some pretty good and interesting discussion material here if anyone is inclined. It may help to establish a more informed opinion with regard to the 2 stroke/4stroke debate.
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Topic: So How is a Four Stroke so much better than a Two Stroke? (Read 4596 times)
