8 50hp outboard shootout

[sean-nós]

Eight-Way 50 HP Outboard Shootout
Lee Boyt
Trailer Boats

August 30, 2009

In the current economic climate, many of us are considering affordable, mid-size boats with more efficient engines. It was in this mindset that we decided to run the current crop of 50 hp outboards to see how they stack up. In total, they numbered eight — the most ambitious engine comparison we have undertaken.

Alumacraft Boats loaned us a corresponding number of its popular Classic 165 CS single side-console aluminum fishing boats. This 16½-foot craft proved to be not only a great platform for the engines, but a surprisingly dry, good-riding boat. Every boat was as identical as humanly possible, the fuel tanks topped off before heading to the lake; the only differences were the color schemes.


Among the eight 20-inch-shaft outboards were four electronically fuel-injected (EFI) four-strokes, two direct-fuel-injected (DFI) two-strokes, and two carbureted two-strokes — a fine mix of new and old technology for our tests. If you count, there are six engine companies — Evinrude, Honda, Mercury, Suzuki, Tohatsu and Yamaha. So why eight 50 hp outboards? Mercury and Yamaha each had two entries — carbureted two-stroke and EFI four-stroke outboards.

We conducted our tests on German Lake near the Alumacraft factory in St. Peter, Minn. ?

Overcast skies, with the threat of rain, temps hovering in the 50s, southeast winds gusting to 20 mph, and 1½-foot seas made it a challenging day, but we forged ahead. The engine company reps drove their respective boats while we gathered the test data. Let’s look at the results.


HOLESHOT
A trio of two-strokes dominated in this category. The Mercury 50 two-stroke won the holeshot contest, with a 0-20 mph time of 5.6 seconds. The Tohatsu DFI two-stroke ran a 6.4, while the Yamaha two-stroke was close behind with a 6.6. Two-strokes are lighter and have less rotating mass than a four-stroke, allowing two-strokes to spin up faster and get underway quicker.

TOP SPEED
These outboards are not known for blistering speed, but some boaters may consider this an important factor. Interestingly, the four-strokes from Honda (35.1 mph) and Mercury (35 mph) won the speed competition. The two-stroke Merc finished third with 34.5 mph. The fact that a couple of four-strokes outran the pack may mean that four-strokes are indeed taking over the speed crown long held by two-strokes.

FUEL EFFICIENCY
Which of the 50s is the cheapest to feed? In terms of optimum cruising economy, the four-strokes from Mercury, Honda and Suzuki took the top three spots with 10.7, 10.6 and 9.1 mpg, respectively. The most efficient outboard got a full 3 mpg better than the least efficient — its carbureted two-stroke counterpart. That is a stunning difference. The DFI two-strokes from Evinrude and Tohatsu were in the middle of the pack, each getting around 9 mpg.

THE SOUND OF IT
Quality of a boating experience can be influenced by the noise levels in the boat — the engine’s sound being the one of the biggest factors. Contrary to popular belief, we run our engines the most at idle, followed by mid-range cruising speed, seldom pushing the full-throttle limit, thus the importance of the idle and cruise sound levels. At idle, the Honda was the quietest, registering just 53 decibels (dBa) — eight dBa quieter than the second place Suzuki. At cruising speed and wide-open throttle, there was relative parity across the board, but the Merc four-stroke was quietest in both with 78 and 88 dBa, respectively.

Of all the contestants, which are the least expensive? Old technology engines — read “carbureted” — are cheapest. Why the big price difference between the carbureted two-stroke outboards and the other engines? These engines cost less because there is no computer to manage the air/fuel mixture or the ignition and fuel injector timing — whereas the other six 50 hp outboards incorporate sophisticated computerized engine management systems that add to the price tag.

THE RIGHT OUTBOARD
All of these outboards are outstanding products that, with a little care, should provide years of loyal service. Based on retail pricing, the carbureted two-strokes require the least initial investment and tend to have the strongest holeshot, yet get the poorest fuel economy and have a larger negative impact on the environment when compared to the DFI two-stroke or EFI four-stroke outboards. The DFI two-strokes and four-strokes generally are faster, more fuel efficient, and dramatically better for the environment than the old-school carbureted two-strokes.

At the end of the day, you will have to decide what is most important to you.



BONUS WEB INFORMATION
THRIFTY FIFTIES
SPEED & FUEL DATA

Below are the full test data charts for speed and fuel consumption from our 50 hp outboard shootout. As a reminder, we tested all of the outboards on Alumacraft Classic 165 CS with a hull weight of 865 pounds (per Alumacraft), two adult males (including the author and the respective outboard factory tech rep), test gear and 20 gallons of gasoline at the beginning of each test. Air temperature hovered around 50 degrees F, and lake conditions were breezy and choppy. A legend for the footnotes to each chart is at the very end of this report.

EVINRUDE E-TEC 50

Engine Speed Fuel Range1

(rpm) (mph) (gph) (mpg) (miles)

1000 3.3 0.1 33.0 594

1500 4.7 0.3 15.7 282

2000 5.9 0.6 9.8 176

2500 7.0 1.1 6.4 115

3000 9.5 1.6 5.9 106

3500 16.5 1.9 8.7 156

40002 21.0 2.3 9.0 162

4500 24.2 2.7 8.9 160

5000 27.7 3.2 8.6 154

5500 30.8 4.3 7.2 129

56503 31.2 4.6 6.8 122

55304 30.3 4.6 6.6 118

Avg. 30.8



HONDA BF50

Engine Speed Fuel Range1

(rpm) (mph) (gph) (mpg) (miles)

1000 2.3 ****** ***** *****

1500 4.6 ****** ***** *****

2000 5.8 0.7 8.3 149

2500 6.4 1.1 5.8 104

3000 7.7 1.5 5.1 92

3500 15.3 1.6 9.6 172

4000 19.7 1.9 10.4 187

45002 23.4 2.2 10.6 190

5000 28.7 3.9 7.4 133

5500 30.7 4.4 7.0 126

59503 35.0 4.6 7.6 136

59404 35.1 4.6 7.6 136

Avg. 35.1



MERCURY 50 HP TWO-STROKE

Engine Speed Fuel Range1

(rpm) (mph) (gph) (mpg) (miles)

1000 3.0 1.1 2.7 49

1500 4.8 1.0 4.8 86

2000 6.3 1.5 4.2 75

2500 7.3 2.0 3.6 64

3000 9.6 2.5 3.8 68

3500 18.4 2.6 7.1 127

40002 24.0 3.1 7.7 138

4500 27.6 4.0 6.9 124

5000 31.3 4.7 6.6 118

55003 35.2 5.5 6.4 115

54004 33.7 6.3 5.3 95

Avg. 34.5



MERCURY 50 EFI FOUR-STROKE

Engine Speed Fuel Range1

(rpm) (mph) (gph) (mpg) (miles)

1000 3.5 0.2 17.5 315

1500 4.8 0.4 12.0 216

2000 5.9 0.6 9.8 176

2500 7.1 1.0 7.1 127

3000 7.9 1.5 5.3 95

3500 17.1 1.5 5.3 95

40002 22.4 2.1 10.7 192

4500 27.4 2.8 9.8 176

5000 30.0 3.2 9.4 169

5500 30.6 4.1 7.5 135

59003 36.4 4.5 8.1 145

57004 33.6 4.5 7.5 135

Avg. 35.0



SUZUKI DF50

Engine Speed Fuel Range1

(rpm) (mph) (gph) (mpg) (miles)

1000 2.5 0.1 25.0 450

1500 3.9 0.2 19.5 351

2000 5.2 0.5 10.4 187

2500 6.0 0.8 7.5 135

3000 6.9 1.2 5.8 104

3500 9.2 1.8 5.1 91

4000 17.0 2.0 8.5 153

45002 21.9 2.4 9.1 163

5000 23.8 2.9 8.2 147

5500 26.5 3.3 8.0 144

6000 31.1 4.3 7.2 129

64503 33.8 4.4 7.7 138

64004 32.4 4.5 7.2 129

Avg. 33.1



TOHATSU MD50

Engine Speed Fuel Range1

(rpm) (mph) (gph) (mpg) (miles)

1000 3.5 ****** ***** *****

1500 4.7 0.2 23.5 423

2000 6.2 0.4 15.5 279

2500 6.6 0.8 8.2 147

3000 8.5 1.7 5.0 90

3500 14.9 1.8 8.3 149

40002 19.7 2.2 8.9 160

4500 24.0 2.8 8.6 154

5000 27.3 3.7 7.4 133

5500 30.3 4.5 6.7 120

57503 33.1 5.1 6.5 117

58004 33.4 5.3 6.3 113

Avg. 33.3



YAMAHA 50 TWO-STROKE

Engine Speed Fuel Range1

(rpm) (mph) (gph) (mpg) (miles)

1000 4.1 0.6 6.8 122

1500 5.1 0.9 5.7 102

2000 6.4 1.3 4.9 88

2500 7.2 1.8 4.0 72

3000 10.5 2.2 4.8 86

3500 19.0 2.4 7.9 142

40002 22.8 2.8 8.1 145

4500 26.5 4.1 6.5 117

5000 29.7 4.9 6.1 109

54003 33.6 5.7 5.9 106

53004 31.6 5.6 5.6 100

Avg. 32.6



YAMAHA F50

Engine Speed Fuel Range1

(rpm) (mph) (gph) (mpg) (miles)

1000 2.8 0.3 9.3 167

1500 4.3 0.6 7.2 129

2000 5.6 0.9 6.2 111

2500 6.4 1.2 5.3 95

3000 7.2 1.8 4.0 72

3500 14.8 1.9 7.9 142

40002 19.2 2.2 8.7 156

4500 22.0 3.1 7.1 127

5000 25.5 3.3 7.7 138

5500 29.4 4.7 6.3 113

58003 32.2 4.8 6.7 120

58004 30.2 4.6 6.6 118

Avg. 31.2



FOOTNOTES:

1 Based on 90% fuel capacity

2 Optimum cruise speed

3 Downwind

4 Upwind