Two Stroke vs. Four Stroke Outboard Motors:

EPA Requirements:

The Environment Protection Agency has said that each outboard motor manufacturer must decrease overall emissions of its entire line by a certain percentage by the year 2006; this does not mean that all motors in a line must be replaced. Some manufacturers will have a combination of four strokes and two strokes, depending on what is best for each horsepower. How manufacturers decrease their engine line's emission is up to them.

How New EPA Requirements Affect Consumers:

New four stroke motors are designed to meet emission-reduction EPA requirements for 2006. However, engine owners are in no way responsible for making changes to existing engines to meet these requirements. Therefore, if you already have a two stroke engine before 2006, you will be able to use that engine for as long as you like.

Four Stroke vs. Two Stroke Cost Factors:

Purchase costs: In general, four stroke motors cost about 25% more upfront to purchase than two stroke engines.

Operating costs: Four stroke motors are more fuel-efficient than two stroke engines, so fuel costs are lower. Over time, the savings in fuel expenses may compensate for the higher purchase cost of four stroke engines.

Maintenance costs: For basic maintenance, four stroke engines use fewer spark plugs than two strokes but need periodic checking of crankcase oil level, and regular oil and filter changes. For larger repair issues, four stroke repairs are generally more expensive and involved than for two stroke engines, simply because there are more components in a four stroke engine.

Four Stroke vs. Two Stroke Performance:

Four stroke engine exhaust is cleaner and basically smokeless, because unlike two stroke engines, no oil is mixed with gas.

Two stroke engines generally weigh less than four stroke engines of comparable horsepower.

Four stroke engines are quieter and smoother-running.

Power is not an issue because horsepower ratings are standard regardless of the technology being used

Specific Four Stroke Issues:

There are specific features of four strokes that need to b addressed, such as proper storage with head up, periodic maintenance, and initial set-up (four strokes are shipped without oil in the crankcase and oil must be added before operation). As with any outboard motor, we encourage you to read your owner's manual before operating a four stroke.

"Should I buy a four stroke or a two stroke outboard motor?"

More and more boaters are asking this question, and there is no simple answer. Instead, you need to evaluate your circumstances, needs and priorities. The information included here should give you a clearer understanding of the advantages of both four stroke and two stroke engines and help you make you decision based on the facts.

Which choice is right for you?

If up-front cost and engine weight are important to you, a two stroke engine could be your best option. However, if the pros of four stroke engines outweigh these factors, you might want to purchase a four stroke engine. Whichever you buy, you'll be able to continue to use it for as long as it lasts.

After reviewing this information, you should ask our your salesperson questions based on your specific boat and motor requirements.

A Consumer Service of Marubeni Engine & Power Corp., distributor of Nissan Marine and Tohatsu Outboards.