Mercury Outboard Motors

   In order to better understand how the Mercury outboard evolved, we must start our production history with the Thor outboard motor.

   The Thor Outboard Motor was the creation of Mr. Thorwald Hansen. Prior to developing his outboard motor, Mr. Hansen was vice President of manufacturing for A.O. Smith Corporation, a company that manufactured automobile frames.

   In 1934 he founded Cedarburg Manufacturing Company located in Cedarburg, Wisconsin. The Thor outboard was unique, in that it was mostly made from stampings. The crankcase down to the lower unit, were all made from stampings. Most halves were nut and bolted together, although some were welded.

   The use of these 1/8 inch steel stampings in stress areas actually made the outboard very strong. The use of mild Steel for ease of production, caused early corrosion in fresh water and obviously accelerated in salt water. It is believed that, these early signs of rusting caused concern with potential customers.

   In 1938 Thor produced the first inline 3 cylinder outboard, called the "Thor Pyramid Three". The Thor outboard had some other issues, over and above the corrosion problems. These could all have been over come, but as with so many small companies financial difficulties caused Mr. Hansen to sell the company in 1939.

   The Cedarburg Manufacturing Company was sold to Carl Kiekhaefer for 25,000. Mr. Kiekhaefer was a young engineer and had intended to use the facilities for manufacturing electrical devices.

   Upon take over of the factory, Mr. Kiekhaefer found several hundred Thor outboards that had been returned from Montgomery Wards as being defective. Needing cash, he rebuilt and improved these outboards and convinced Montgomery Wards to try them again.

   Montgomery Wards was so impressed with improvements, they placed another large order with Mr. Kiekhaefer. Like they say, life turns on a dime. It was this order from Montgomery Wards that caused Mr. Kiekhaefer to enter the outboard motor field.

   In 1939 Kiekhaefer manufactured a single, alternate twin and the inline 3 cylinder with the Thor brand name. Using material and tooling that was still in place. He renamed the factory the Kiekhaefer Corporation.

   In 1940 Mr. Kiekhaefer had totally redesigned the Thor outboard. He took the name of the Roman Messenger of the Gods and named his new outboard Mercury . He continued to manufacture outboards for Montgomery Wards under the "Sea King" brand and also under the brand name Mercury.

   The production of the Thor outboard motor and history ends in 1939. By the following year Mr. Kiekhaefer had totally re-designed his 3 horsepower "Streamliner" outboard with many new innovations.

   The outboard was ready for the 1940 New York Boat Show. In a home made tradeshow booth, he displayed his outboards and received orders for over 15,000 of them. The Mercury outboard was on its way to making history.

   When the War broke out in 1941 most all outboard production shut down until 1946. During the war years Kiekhaefer had won a government contract to manufacture a lighter weight Chain Saw. By the end of the War, Kiekhaefer was the largest producer of chain saws in the world. His company also became an authority on radio-controlled aircraft using their two-cycle engine technology.

   Kiekhaefer had build up a lot of valuable engine experience during the war years. Anticipating a high demand for outboard motors after the War, he was ready. With constant improvements to his design, Kiekhaefer and his Mercury outboard sales left many of his competitors sinking with outdated designs.

   Kiekhaefer really got his start by manufacturing outboards for Montgomery Wards. A small horsepower Kiekhaefer outboard showed up in the Sea King line from 1940 through 1947 and possibly later. He also contracted with Western Auto to manufacture a line of outboards under the Wizard brand name. Although not popular with regular marine dealers, this kept production levels higher. Being relatively new to the business, this made good business since.

   He produced the Wizard outboard from 1940 through 1957. These outboards were a stripped down version of his Mercury line. Basic parts were interchangeable, but there were some different in the Wizard over and above the cosmetic different.

   By the late 40's Kiekhaefer had run out of room at the Cedarburg factory. He purchased a dairy farm in fond du Lac, Wisconsin. This was to be Mercury's new home and the factory remains there today. Later other Parts, Service, Research and Testing locations were added in Wisconsin and Florida.

   Kiekhaefer continued to revolutionize the outboard industry in the coming years by introducing new innovations in his Mercury outboards.

   Our interest in this brief history is limited to some basic facts that follow the production history of the Mercury outboard. There are many in-depth books and articles on the Mercury outboard and Mr. Kiekhaefer. One such book is Peter Hunn's "The Old Outboard Book".

   The late 50's and early 60's saw major changes to the Kiekhaefer outboard motor. Racing lower units were gone in 1959 and the well know "Mark" models were gone in 1960. The new model number system was to add a zero to the horsepower. Examples: 15 hp = Merc 150 and 100 hp = Merc 1000, there were some exceptions.

   The Kiekhaefer Corporation merged with the Brunswick Corporation in 1961. Brunswick brought lots of capital, other leisure products and a world wide market. Shortly afterwards the Kiekhaefer name was removed in favor of Mercury Marine.

   Mr. Kiekhaefer stayed with Brunswick for awhile, but left the corporation in 1970. In this same year Mr. Kiekhaefer brought Kiekhaefer Aeromarine to life. A company he established in 1946 that was not acquired by Brunswick.

   He focused on racing and high performance. Along with special accessories like Props, Trim Tabs, Shift Controls, etc. He produced some class winning Snowmobile engines in 1971 and 1972. It was said that he had some outboards on the drawing boards, but to our knowledge never produced.

   Mr. E Carl Kiekhaefer passed away on October 5, 1983. The Kiekhaefer Aeromarine name and facilities were sold to Brunswick Corporation in 1990 by Carl's son Fred.

   With decades of changes, the Mercury outboard is still with us today. Brunswick Corporation added Mariner outboard in 1975 and purchased many boat manufacturers over the years. When they purchased the Bayliner Boat Company in 1986 they inherited the Force outboard (formally Chrysler ) line as well.

   The Mariner outboards under 50 horsepower were manufactured by Yamaha and other Japanese manufacturers. The 50 horsepower and up were made by Mercury. Brunswick continued making the Force outboard and gradually phased manufacturing to Mercury units with the Force Name. The lower horsepower Forces were the last to go. The Force and the Mariner names were gone in 2000.

   Through different types of oiling systems and numerous other changes through the last 50 some years, Mercury is still alive and doing well.

   Please click on model year guide below.

   Hard core parts for these outboards are getting more difficult to find as time goes on. Many older outboards used common Ignition and Carburetor venders for that period. Discount Marine Parts has Ignition and Carburetor repair kits for most all of these older outboards. If we don't have what your looking for, we have many sources to locate your part. Obviously some parts are just not available. We can sometimes find it used and often we have the part made if there is enough demand. Discount Marine Parts has a large inventory of parts for most brands of American made Outboards, Inboards and Sterndrives. We also have most parts and service manuals available.

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Mercury Model Number List

K1 - Mark 78E                    

Mercury   Model Year Guide

1940 - 1952       1953 - 1959       19?? - 19??       19?? - 19??       19?? - 19??       19?? - 19??       19?? - 19??

19?? - 19??       19?? - 19??       19??- 19??

Discount Marine Parts
Phone       4524 D Road  •  PO Box 98       Fax
906-466-2180       Bark River, MI 49807       906-466-0217

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Last Modified: 4/2/04