3.9 outboard engine

Year built / model 1972 - 1974 Crescent 3.9 Monarch 3.9 a / Archimedes Penta 39a
Power Class 3.9 hp 3200/4000
Engine 1 cyl. 2-stroke (no engine cowl, från1972, mid engine hood)
Displacement 70 cc
Ignition Flywheel Magneto. Generator 6V 17W
Cooling system Air cooled
Propeller Diam. / pitch 2 leaves 210 / 140 mm
Weight 13 kg
Built-in tank Tank capacity 1.9 liters
Other Omsvängbar 180 degrees. Die-cast rig,

Category:

Education

Tags:

• outboard

[coffeecation]

Hi - I have 3.9 Crescent and need to know about watercooling. One site says there is an intake behind the prop and the water comes out of the little exit hole in the back (Which it isnt so I stopped it) and another say they are air cooled. The only engine fins are at the bottom rear and the rest of the engine has a shroud around it???

[stuartnealis]

@sportwin. I have one of these and can't get it to idle. It also needs some new gears cut, but, one thing at a time! I would be very interested in your manual if you are selling it? I am near Glasgow, Scotland. Let me know, thanks. SN.

[sportwin]

nice motor seems to be running well. I had one and wish I still had it, these motors seem to last and being air cooled, there's no impeller to worry about. I have the manual for this motor if you're interested.