The “Alien” and the “El Tiger” engine – World Exclusive

The “Alien” and the “El Tiger” engine – World Exclusive

The story is based upon the real facts that Clayton Jacobson II, the Jet Ski Inventor supplied to valuable information that add another chapter to the history of Jet Skis.

Words:Vasilis Moraitis
Source:Clayton Jacobson II 

Fourty years after the first stand-up Jet Ski was released in the market Clayton Jacobson II, the Inventor of Jet Ski made his comeback to the sport by appearing at the World Finals, the capital of personal watercraft racing. One of his spectacular engineering innovations, the Freeride Kevlar Jet Ski with the modified snowmobile engine was presented for the first time at the Jettrim Vintage Jet Ski museum. Many people saw it but no one actually knew what was this engine all about.

Therefore, we contact Jacobson II and asked him to explained all the details about the mysterious twin-cylinder rope start engine which was equipped with slide carburetors and external exhaust pipe. So Clayton Jacobson II puts everything down to writing in his own words: “The photo of me, Clayton Jacobson in front of the 1981 “Alien”, tuned Pipe Variation at the Jettrim Vintage Jet Ski Museum, Lake Havasu City, Arizona 2013. The large white drawing in the background above, with my signature in the felt pen over, was from a Personal Watercraft Magazine Party (in my honour), Lake Havasu City 1995. This is the “Marcel” drawing of the original Jacobson Engineering Jet-Ski prototype as built 1971, which until the party was unsigned by me.

PWC Magazine source it somewhere in 1994 while writing the “Inventor and the Invention” story published by Personal Watercraft Magazine, July 1994, reprint in “the book” (Jet Ski Inventor Autobiography).

The full story about the Alien’s 500cc snowmobile motor (rope start) installed is a follows: In the 60’s I designed (invented) and built “Virus” engine modifications for Bombardier 320cc, 2-cycle snowmobile engine (many championships also the Sea-Doo engine), as related in “the book”.

The problem with the piston ported engines was the intake opening and closing is at the same time “degrees” which is an inherit problem (no overlap). My design featured a reed valve intake opening below a piston valve intake opening. This gave the early opening and early closing gratly improving performance. This technology was very successful for the Bombardier racing team, following which, the head guy from Bombardier left to join Artic Snowmobiles. The El Tigre engine was then born with that following feature. The performance was very successful (winning many world titles), billed as 100hp, 500cc twin with a separate tuned exhaust for each cylinder. A single huge slide valve carburettor replaced the two fitted on each cylinder of the Virus. The Artic “El Tigre” engine was manufactured by Suzuki in Japan for Artic, all of which was without my knowledge or consent.

Then a full circle occurred, I was working on the Wet-Bike project for Nelson Tyler. Nelson had picked the Suzuki outboard power head and delegated me to engineer the jet pump, transmission, exhaust etc. as shown on page 135, E11 in “the book”.

I had constructed a test bed in the swimming pool for the prototype, which would measure the thrust, velocity performance, temperatures, adjustments and endurance etc.

Suzuki had been similarly doing the same for years, developing a jet drive system. Well, it was like “D’ej’a vu”, Bombardier initially, 1968 had challenged my horsepower claims on my Virus modification Japan now challenged my 1974 figures saying it was impossible for my Jet Pump to produce the thrust figures I was quoting with their engine. This went back and forth several times and then five Suzuki engineers from Japan came to Tyler Camera Systems in North Hollywood. There they verified the performance as accurate, inspected everything, smiled a lot, bowed a lot for several days, then just got in their van and pissed off.

Well, it must have been embarrassing to say the least for the factory engineers. Thus I learned of Suzuki, which supplied Artic which now licenced Wet-Bike from Tyler. See Brochure on page 141 of “the book”. However, I did end up with an El Tigre Engine that I sawed the transmission off of and built the El Tirge “Alien” five years later which at the time 1980-81 was far faster and lighter than any other, which horsepower required making an overlapping blade configuration for the impeller. Super light, super strong for surf nuts etc. Kevlar hulls and hoods only, the rest was up to the power. Seven in all were hand built, for special people.

Racing, open to improvement and innovation was among the things, which I wanted to promote in putting on the races. See the 1981 flyer in “the book” on page 237. Racing open to innovations etc and to teach how to design and organize racing events properly. The Kawasaki people responded by boycotting the event, typically small minded. It all came to pass despite Kawasaki.”

NOTE: This story would not have been written if I had not had the chance to meet Clayton Jacobson II and also if I had not read his autobiography “Jet Ski Inventor Autobiography”.

Many thanks to Gary Hart from Jettrim who kept listening to me when I was telling him over and over again “try to bring Clayton at Jettrim Vintage Jet Ski Museum”.

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