Study of Two and Four Stroke Outboard Marine Engine Exhaust Emissions Using a Total Dilution Sampling System

The exhaust emissions from small engines in general and marine engines in particular have come under scrutiny over the past few years as new exhaust emission regulations have been proposed and put into force. The standard method for exhaust emission sampling of outboard marine engines is to analyze raw exhaust in the exhaust manifold of the engine. In this study a total dilution sampling system for the gaseous emissions, similar to what is used for light and heavy duty vehicles and engines, and a separate water sampling method were used to evaluate the exhaust emissions from stock two and four stroke outboard marine engines.