Two stroke motors were the favored power-plants for snowmobiles beginning in the early 1960's to the mid-1970's. The comparatively light weight to horsepower ratio and compact design was more desirable than the four stroke standards of the time. Fewer moving parts and more horsepower at higher RPM made them more attractive to manufacturers and consumers alike as snowmobiles made the transition from rear engine utility vehicles to front engine sport machines.
German motors were adapted to snowmobile use from industrial stationary units used to power pumps, generators, and the like. Most were fitted with the German Bosch magneto ignition system and, of course, the recommended spark plug was Bosch. Diaphram carbs replaced the float bowls.
Gutbrod-Werke GMBH in West Germany manufactured motors used by the Bolens Division of FMC Corporation and bore their name. Multi-cylinder models from 310cc to 438cc were produced from 1969 to 1972. In 1971 they made available the first three cylinder motor in a production snowmobile. Their engine design was unique in that the crankshaft was split and coupled together. Castrol at 20 to 1 was the preferred fuel to oil mix.
Hirth Motors of Kreis Ludwigsburg, West Germany, were distributed by Wisconsin Motor Corporation in Milwaukee.
Hirth's were utilized by many Canadian and American manufacturers as early as 1963 in the Sno Bug.
Motor sizes ranged from the 10 horsepower, 246cc 81 R, to the mighty 793cc three cylinder 230 R "Honker," which turned 80 horsepower and many heads at the race track.
The 171 R 634cc was also a very popular and successful model. Hirth even offered a 493cc 24 horsepower opposed twin, the 180 R.
Hirth motors were cooled by centrifugal fan until 1970 when they switched to axial fan (belt driven) cooling.
The recommended fuel to oil mix was 25 to 1.
JLO engines were manufactured in Pinneberg, West Germany, and distributed from Syracuse, New York.
The first two stroke Ski-Doo was powered by an 8 horsepower JLO in 1961. JLO made many models from the tiny L99 used in the Yard Man Sno Cub to the free air 3 cylinder 650cc used by Arctic in the King Kat.
JLO twins were cooled by centrifugal fan until a design change in 1970 and a switch to the axial fanT
Rockwell Manufacturing bought JLO on Oct. 1, 1968, then billed as the largest manufacturer of small engines in West Germany with a heritage of over half a century of quality performance.
They again changed hands and homes, and in 1975, after Scorpion moved the operation to Crosby, Minnesota, JLO-Rockwell became Cuyuna, named for the nearby Iron Range. Cuyuna became the only American-made snowmobile engine at that time.
Fuel to oil ratio went from 20 to 1 on early models to 40 to 1 on later models. JLO's were used in snowmobiles longer than any other German manufacturer.
Lloyd Motoren Werke GMBH of West Germany produced two models used in snowmobiles. They were also used in small automobiles.
The 386cc twin was used by Yukon King in 1968-69, Sno Prince in 1969-70, Ski Daddler 1969 and Herters in 1970.
Cooled by centrifugal fan, the fuel to oil mixture was 40 to 1, somewhat lean for the era.
The Lloyd engine blazed its way into racing history when the 1968 Yukon King factory team won every race they entered in the 295cc stock class.
The North American distributor was in Kitchener, Ontario.
Sachs motors were made by Fichtel & Sachs AG in West Germany. They had distributors in Quebec and New Jersey.
Motor sizes ranged from the SA 280 277cc to the SA 2-740C, 735cc. Sachs made several performance models, the SS and C fan cooled and the R Twins were cooled by axial fan and the suggested fuel to oil ratio was 25 to 1.
Sachs motors found their way into many different snowmobiles, most notably the Canadian Alouette and Eskimo.
Sachs very probably had the most durable and dependable recoil starter of all the German motors.
The Wankel Rotary engine was invented by Felix Wankel and made by Fichtel & Sachs. The 303cc RC1-18.5 was manufactured for Curtiss-Wright Corporation from New Jersey in 1968 to 1970. The fuel mix was 40 to 1.
Its successor, the KM 914B, was made from 1971 to 1972. The fuel to oil ratio was 50 to 1. Both models used Tillotson HL diaphram carburetors, and both produced 19 horsepower, 303cc.
The KM24 was next in line and was in service until 1975. It used a mechanical fuel pump that was mounted on the rewind. Fuel to oil ratio was 50 to 1 and was rated at 23 horsepower, 294cc.
Rotary oil was recommended for the KM24, while Shell Rotella, Mobilmix TT, and Essolube HD30 were among the preffered oils for the earlier models.
Polaris, Alouette, Skiroule and Arctic Cat all featured the Wankel Rotary at one time or another. Cat was the last to use the Wankel in 1975.
Many incorrectly surmise that Rotax, the mainstay motor of Ski-Doo, was a German product While there were many similarities, Rotax engines were manufactured in Austria.
Motosacoche, or Mag motors used in Ski Daddler,- were manufactured in Switzerland, as were early Kohler two strokes.
By the early 1970's the demand for more power and easier starting brought Japanese motors into the limelight. Fuji, Kawasaki, Suzuki, Yamaha and others became the exclusive power plants for most of the major brands.
Smaller manufacturers began to die off as the snowmobile market tightened, taking German motors with them as they faded into history.
Reprinted with permission.