Outboard Motor

At this years Miami Boat Show, Bombardier introduced their new line of 2 and 3 cylinder DFI engines, covering the range from 40 to 90 HP. The 40, 50, and 60 HP models were two cylinders, and the 75 and 90 HP models had three. This leaves only a small fraction of the outboard engine market not covered by both four strokes and DFI two-strokes.

These engines have completely new injection and electronic systems, and are microprocessor controlled in all their vital functions. The electronically controlled oiling system, while still injecting and consuming oil as two strokes do, uses about half the oil per horsepower than the larger DFI two strokes. Also, the engines are said to be maintenance free for three years, which is the length of the warranty period. The integral oil tanks hold enough oil for one full "normal" operating season, and the engines require no winterization. The engines also weigh considerably less than a comperable four stroke.

Millers Boating Center recently decided to hold their own 2 stroke vs 4 stroke fuel economy test. A new 225 HP Mercury OptiMax and a new 225 HP Mercury FourStroke were started at the same time and were supplied with exactly one gallon of fuel. Both were allowed to run at the factory set idle speed until they ran out of fuel. Which do you think ran longer? At 95 minutes the 225 FourStroke exhausted its fuel supply. The OptiMax continued to run for an additional 62 minutes. This demonstrates that the 2 stroke delivers greater economy at trolling speeds than the 4 stroke.

Now that you have rebuilt the carburetor, installed it on the motor and set the synchronization, it's time to start the motor and adjust the carburetor. To do a proper job of adjusting, the motor should be on the boat and under way, or at least in a large enough test tank to put the motor in gear and rev it up all the way. It is meaningless to adjust the carb with the engine in neutral, or with the motor on earmuffs. There must be a load on the motor.

After you start the motor, let it warm up for a few minutes, then put it in gear and rev it up all the way. If the motor has an adjustable high speed, slowly turn the mixture screw in (clockwise) until the engine begins to die from running too lean, then back it out 1/4 turn and tighten the packings to stop it from moving from vibration. If the motor has a fixed high speed, as most newer motors do, rev it up anyway to be sure the high speed jets are open.

Slow the engine down to an idle speed, and slowly turn the low speed adjustment in (clockwise) until the engine begins to pop and miss from running too lean. Then back it out from 1/4 to 1/2 turn and tighten the packings. You may have to fine tune the low speed adjustment at a later time, because it can vary with weather conditions and usage. Reinstall any knobs on the mixture screws.

"Behind the Mercury 6-in-line design are tens of thousands of Kiekhaefer engines- V-fours, opposed fours, radial engines, big bore twins, V-twins...designed, built and tested by Kiekhaefer since 1939 to prove the best design for Mercury multi-cylinder high horsepower outboards. Kiekhaefer found that only the in-line engine was compact enough, smooth enough, quiet enough and efficient enough to deliver all the benefits the public wanted in big outboards."

"SO FAR AHEAD NO CHALLENGERS ARE IN SIGHT! With all its mighty power and astonishing performance the Mark 75 is so simple to control that a child can safely handle it. A single control lever does the work...just push the button to start, push forward to go ahead, pull back to reverse--action so fast, so easy, so foolproof you can actually rock the boat back and forth! The Mark 75 is direct-reversing, simply by changing the direction of crankshaft rotation-- no gear-shifting, no bulky lower unit gears, no excess weight...another terrific Mercury first!"

This month we will cover ESKA outboards. Eska began selling its first outboard in 1960, borrowing many designs from Clinton outboards. They were about as simple as an outboard could be, and served as a good, inexpensive way for many people to give up their oars and become powerboaters. Eska took a two-cycle, single cylinder air cooled powerhead built by Tecumseh and attached it to a Clinton lower unit. They remained pretty much unchanged until 1973, when Eska introduced a two cylinder water cooled outboard producing 9.9 and 15 HP. This continued until 1987 when Eska went out of business. Eska supplied motors to many companies such as Sears, Pennys, Grants and others. Parts are still fairly easy to get, mainly due to the large volume of motors produced. I don't have any model number info prior to 1965.