Outboard Motors

 Outboard motors are extremely important out here.  Anyone who has a boat, uses an outboard motor.  I chose a 250 HP motor with the idea that they owned a commercial fishing boat and needed to replace it so they need to learn to do certain comparsons.

When I began developing this activity, I knew absolutely nothing about boat motors.  It was after I finished writing this that I found out the size motor I chose was a bit excessive for taking your boat up river.  I discovered the 250 horsepower is actually more of a motor for a commercial boat.

When I learned that, I went ahead and used the idea of a commercial fishing boat because so many people in this village go commercial fishing in the summer and earn enough money to live the rest of the year.

I chose the four most popular brands used out here.  I had to ask another teacher but he was more than willing to help me out.

So now you see the activity I created.

Outboard Boat Motors

1.Calculate the power to weight ratio by dividing power in HP by the dry weight.              So HP/weight in pounds.

2. Calculate the bore - stroke ratio by dividing the bore measurement by the stroke measurement.  So bore/stroke

3.  Find average gas consumption by following the appropriate formula

     For a 2 cycle engine - HP/12

     For a 4 cycle engine - HP/15

4. Find the percent  between the answer in Step 3 and the GPH listed.

For instance if you have a  250/10 = 25 gph.

The published GPH is 19.2. 

To find the percent of the calculated is published GPH/calculated GPH.

So I’d take 19.2/25 = .768

Take .768 x 100 - 76.8. so the percent of the calculated is 78.6 %

5.  Find the torque by multiplying HP x 5252 and dividing that answer by RPM.

 So (HP x 5252)/RPM

Write the answers in the following table.

Motor	Mercury Sea Pro 250	Evinrude 250	Yamaha F-250	Honda BF 250
Power to weight Ratio
Bore stroke ratio
Average gas consumption
Percent of GPH listed/calculated GPH
Torque

1. Based on the results in the table, make a recommendation on which outboard engine you would suggest I buy for my fishing boat.  Use the data to support your answer.

2.  Which motor would you recommend based on your personal experience.  Give me concrete reasons for your recommendation.

If you would like to change the engines out for something smaller, feel free to do so.  You can also choose the brands you are more familiar with.  Let me know what you think, I'd love to hear.  Next time, I'll present one of chair saws.  Have a great day.