CONTINUOUSWAVE

Test results from recent re-powering of a SPORT 15:

BOAT: 1978 SPORT 15
ENGINE: 2023 Suzuki DF60a
TEST CREW: two adults
FUEL: 6-gallons

PROPELLER PowerTech
FAMILY or MODEL: TBA
MATERIAL: Stainless steel
NUMBER OF BLADES: TBA
PITCH: 17-pitch
DIAMETER: possibly is 11.25-inches

Wide-open Throttle Performance
ENGINE SPEED: cited only as just below the rev-limiter of 6,300-RPM
ENGINE TRIM: cited as 6-percent
BOAT SPEED: 42 to 43-MPH

BOAT SPEED and FUEL ECONOMY: see below.

Please mention more detail:

• number of cylinders for DF60a
• displacement of DF60a
• weight of DF60a
• block configuration of DF60a
• engine gear ratio
• propeller model or family designation
• propeller number of blades
• engine speed at full-throttle reported boat speed
• boat speed for 15-MPG fuel economy

The boat looks very nice with the white engine paint.

Please add-

Engine mounting height. How many empty holes above the top bolt?
Prop manufacturer, model and size. i.e. PowerTech SCD3 13x17.
Speed and rpm when initially on plane.
Speed at each 1000 rpm
Top speed and rpm at full throttle (WOT)

WOT speed of 43 MPH in your Sport 15 must have been exciting.

It was. Very smooth and comfortable, however, when compared to the old 2-stroke I had before screaming in my ear.

One adult on board, only 6-gallons of fuel:
ENGINE SPEED = 3400 RPM
BOAT SPEED = 22.4 MPH
FUEL FLOW = 1.4 GPH
ECONOMY = 15.7 MPG

[As seen in Figure 1 above the SUZUKI DF60a engine] looks big or oversized on the transom of the SPORT 15.

Q1: how does the size of SUZUKI DF60a compare to the YAMAHA F70?

The Suzuki DF60a may appear larger but weighs less than the Yamaha.

Suzuki DF60a = 229-lbs
Yamaha F70 = 254-lbs

grizzly wrote:[As seen in Figure 1 above the SUZUKI DF60a engine] looks big or oversized on the transom of the SPORT 15.

The DF60a engine does appear in Figure 1 as a rather large engine for the SPORT 15, but I think that appearance is related to the way the boat is arranged in the photograph and the position of the camera.

The Suzuki DF60a has a small gear case, which accounts for some of the [difference] in engine weight [perhaps means compared to the Yamaha F70 engine which by inference is presumed to have a large gear case].





The appearance of the engine as being "large" may be due to the engine mounting height in use. The [shallow splash well of the SPORT 15 boat] would not allow the engine to be mounted any lower.

The data [given in an earlier post to this thread] were [computed from the speed solution] from a GPS receiver; the engine trim was at "zero."

IMPORTANT NOTE TO PHOTOGRAPHER: DO NOT HOLD YOUR CAMERA IN THE VERTICAL OR PORTRAIT ORIENTATION WHEN TAKING PHOTOGRAPHS TO BE USED AS INLINE ILLUSTRATIONS IN HTML.

Figure 3 shows a very nice orientation of the anti-ventilation plate relative to the flow of water around the gear case. I do not see any need to increase the trim OUT from what was used when this image was photographed. The TRIM looks perfect.

What is the engine mounting height of the DF60a engine on the SPORT 15 as measured in units of holes raised from the lowest possible position?

(Second request for this information; reports of performance should always mention the engine mounting height.)

A SPORT 15 boat speed of 42 to 43-MPH is great for the setup [described above in this report on performance of a SPORT 15 with a SUZUKI DF60a engine].

[The engine mounting height is shown below in Figure 4; the engine mounting height is three-holes-up from lowest possible position.]