Mercury MerCruiser has filled a hole in its line of ECT (Emissions Control Technology) sterndrive engines with the introduction of the 4.3 MPI ECT model, a 4.3-liter V6 rated at 220 hp. MerCruiser will now offer seven sterndrive engine packages with exhaust catalysts, ranging from the 135-hp 3.0 MPI ECT to the 430-hp 8.2 MAG H.O. ECT. The 4.3 MPI ECT went into production this month, according to Mercury Marine.

Equipped with a catalyst in the upper portion of each exhaust manifold, the new MerCruiser 4.3 MPI ECT meets all EPA and CARB emissions regulations.

Equipped with a catalyst in the upper portion of each exhaust manifold, the new MerCruiser 4.3 MPI ECT meets all EPA and CARB emissions regulations.

MerCruiser has not previously offered the 4.3-liter V6 engine with a catalyst. The engine was exempt from the most-recent round of EPA exhaust emissions regulations because GM Powertrain, which manufactures the base engine, had told the marine industry it would be dropping production of the 4.3. The EPA granted the exception so marine engine builders would not have to invest in developing a catalyst package for an engine that would only remain on the market for a single season. However, GM later changed its plans, and the 4.3 remains in production and is a popular engine option on small to mid-size runabouts and cruisers.

The other key player in the sterndrive market, Volvo Penta, has announcedĀ  it will not develop a catalyzed version of the 4.3-liter V6, but will offer that engine with either a carburetor or fuel-injection system, with availability limited by the number of low-emissions, catalyzed engines the company sells as it averages those engines into its over-all emissions footprint.

Equipped with a catalyst, the MerCruiser 4.3 MPI ECT meets EPA and California Air Resources Board (CARB) emissions regulations, and can be sold in all US markets. According to Mercury Marine, the 4.3 MPI ECT matches the performance of the non-catalyzed, 220-hp 4.3 MPI engine, and delivers five to 10 percent better fuel economy at cruising speeds, thanks to a more complex engine-management system. Mercury adds that the 4.3 MPI ECT is five percent quieter than the non-catalyzed 4.3 in pass-by noise measurements. The engine is also updated with an easy-to-access oil cap, improved dipstick, and color-coded service points. F

or use in salt water, the 4.3 MPI ECT can be equipped with the MerCruiser SeaCore System, a corrosion-fighting package that includes MerCathodeĀ® active corrosion protection, a closed-cooling system with five-year long-life coolant, and additional stainless steel components. Mercury will continue to produce the 4.3-liter engine without catalysts (with either a carburetor or EFI), but according to the company virtually all of those engines will be for sale outside the US, or in very small numbers for re-power applications. The 4.3 MPI ECT can be rigged with MerCruiser Alpha, Bravo Two and Bravo Three outdrives.