Mercruiser 470 Engine Facts

by Evan Gillespie

Engineer Carl Kiekhaefer didn't have dreams of revolutionizing the marine engine business when he founded Kiekhaefer Corporation in 1940. He wanted to build dairy separators, but a contract to rebuild outboard motors changed the direction that Kiekhaefer Coporation would move. The MerCruiser engine, the first sterndrive powerplant over 100 horsepower, was just one of the many results of Kiekhaefer's detour.

Company History

Kiekhaefer introduced his own outboards, which he called Mercury motors, to enthusiastic buyers at the 1940 New York Boat Show, but the start of World War II derailed his plans once again. Kiekhaefer spent the war building chainsaw motors, but after the war he was back in the boat propulsion business. His Mercury Lightning outboard, introduced in 1947, was a two-cylinder engine that produced 10 horsepower. The Mercury Thunderbolt, a four-cylinder engine delivering 40 horsepower, followed a year later, and the six-cylinder, 60-horsepower Mark 75 was delivered in 1957.

First MerCruiser Engine

In 1961, Kiekhaefer merged with Brunswick Corporation, signaling the beginning of a new era for the company. Its products changed along with its corporate structure, and the first MerCruiser sterndrive engine was introduced in 1961, as well. The sterndrive was a compromise between inboard and outboard engines, and buyers loved the Kiekhaefer interpretation of the concept. The MerCruiser dominated the sterndrive market, and larger versions of the engine were developed in the following years.

1976 MerCruiser 470

The MerCruiser 470 began production in 1976. It was a 3.7-liter inline four-cylinder engine that produced 170 horsepower, a powerful alternative to the 160- and 165-horsepower six-cylinder Mercury engines. The 470 featured a cast aluminum engine block designed by Mercury Marine, the name Kiekhaefer's company had taken in 1969, and the block was mated with an iron cylinder head from the Ford 460 V-8 engine. The same engine block was used in several other MerCruiser engines, including the 170, 190, 485 and 488.

Common Problems

The popular 470 was not without its problems. Its water pump is cam-driven and the pump's seals tend to develop leaks over time. Replacing the seals before a leak can allow the coolant to contaminate the engine oil is critical, or the resulting repair can be costly. Problems with the alternator overheating and eventually burning out are also common, and replacing the original alternator with a more reliable model used on other Mercury sterndrive engines is recommended.

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