Two-Stroke Versus Four Stroke Outboard Motors



If you are like me and I know you are, you have a two stroke outboard motor. That’s because for all intents and purposes, that was all you could buy for many, many years. Two strokes are the king of small engines.

However, these days there is a lot of hype about four stroke outboards and they are gradually gaining ground with the cottage boating community.

What Is The Difference Between Two-Stroke and Four-Stroke Outboard Motors?

There are a couple of reasons behind the shift from two stroke engines to four. The first is the environment. Manufacturers and proponents of four stroke engines are big on telling us that four stroke outboards are a lot easier on the water we run our boats in. For one thing, the oil is not mixed with the gas, and therefore is not burned in the same way, so there is less chance of oil entering the water system.

There is also less smoke with a four stroke, which is also an environmentally friendly way of looking at it.

Today most small engines in use, be they outboard motors, chain saws, many lawn mowers, whipper snippers, are powered by two stroke engines. These are the engines you own that you usually have to mix a little oil into the gas.

I said “usually” because of late, many two strokes are being made with oil injection features that allow the oil to be put in separately, however, regardless of how it gets in the fuel, it still mixes with it and is ultimately burned.

Four stroke engines are like car engines, where the oil is separate from the fuel. Hence the requirement to ‘check your oil level periodically’ or ‘change your oil’ Oil is not mixed with the fuel.

Two stroke outboards are usually lighter, and somewhat faster than four strokes, although technology is catching up with that. Four strokes are quiet running, usually easier to start, and will run slow very smoothly.

But the heavy weight can offset some of this, making them a little less attractive for the small boat operator. Let’s see, more weight, less speed…yup…that is a rule of boating…couple that with a little less get out of the hole power, and you have something that doesn’t appeal to everyone. But…you better get used to it.

The environmentally concerned folks are pushing for the use of fours strokes entirely, and in some cases trying to eliminate the use of two strokes on some lakes.

What’s worse, the tree huggers amongst us, are all for having us use canoes or little electric motors only….oh my god….but I digress.

As I mentioned two stroke outboards have been around for years, and years, at least 70 or 80 years, and let’s face it, for all intents and purposes, they are pretty well refined and trouble free. The other thing is, they last seemingly forever.

I myself am running around my cottage lake with an outboard motor manufactured by Evinrude in 1978. What does that tell you? It tells me that the outboard motor manufacturers, unlike the automobile manufacturers have been slow to catch on to the science of planned obsolescence. In other words, their products are too good and last too long. Not good from an ongoing profit stand point.

So what do you do about that? Well, look for an angle, and in this day and age there is no bigger angle than the environment. Folks are bombarded with bad news about the environment and almost everything is blamed for having detrimental affects on the world around us.

Global warming and climate change have, if nothing else, begun to catch the eye of the public, who are getting concerned. This is a made-to-order opportunity for outboard motor manufacturers to ‘refresh the fleet’ so to speak, by shifting away from tried and true, long lasting two stroke outboards and promote their replacement with four strokes whose reliability and longevity is less well known.

If you can get the environmentally concerned citizens and groups on board, you have a ready made advertising and marketing plan right at your fingertips. Couple that with governments that are excited about looking like they are doing something for the environment and the world is your oyster, especially if those governments start legislating four stroke engine only lakes, or an outright ban on the use of two stroke outboards, which is something some folks would love to see.

Before we add this to the growing list of conspiracy theories that abound on the Internet and elsewhere, I am not saying that this is a grand conspiracy on the part of outboard manufacturers. What I am saying is draw you own conclusions.

Manufacturer’s, who were struggling through declining sales because their products were lasting too long, have been handed a golden opportunity to sell new products to replace the thousands, if not hundreds of thousands, if not millions of outboards in use around the world, regardless of whether or not the new engines are ultimately as good as the old outboards.

One final note. Remember, that regardless of whether or not oil is mixed with the gas as in two stroke engine technology, or used separately as with four strokes, it is still being used.

Four stroke engines, like automobile engines require regular oil changes, which means the old oil has to go somewhere. The assumption being that it is properly recycled. If it isn’t, it could be as hard or harder on the environment as oil that is burned with the gas in two stroke outboard technology.

So there is my two cents worth on two stroke outboard motors and four stroke outboard motors. Which is best I believe remains to be seen, only time will tell, in the meantime, I will keep my little 15 horsepower Evinrude a little longer, old habits die hard…..



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