In some Countries 40 HP is the maximum power allowed to pilot a boat with no specific license.
So, Mercury has many models with this output. Among the 4 stroked ones, two use the 3 cylinder block for 747 cc (45.6 cubic inches) and two share the same 4 pots block of the 60 HP model, with a displacement of 995 cc (60.7 ci). This Mercury EFI 40 Pro is the top of the range, and differs from the actual EFI Orion for the thicker leg and the final ratio of 2.33 instead of 1.81.
The 40 Pro share the advanced technology of Mercury FourStroke range: single overhead camshaft, long stroke for higher torque and faster acceleration even at high loads, electronic fuel injection with a patented system that ensures ignition at the first key-turn and a fuel flow control for better mileage.
The 40 Pro is installed on a Marlin 630 (20 ft 8 in) rib. The water is calm and performance can be fully tested. In 3.5 seconds we are planing, in 20 we are at the cruising speed of around 20 knots. With a heavier load the figures will change, but it’s still peculiar numbers as we are using a three blade propeller 13 inches of diameter. Checking the consumption, we read 16.3 liters per hour (4.3 gallons per hour) at 2000 revs and 20 knots: this grants a nice and “low cost” cruising day. At the minimum planing speed, the data say 3.200 rpm, 9.5 knots and just 7 lph (1.8 gph). This means that the bundle between the Mercury F40 Pro and the Marlin 630 rib is the perfect match for a comfortable, safe and inexpensive way to cruise around.
The Marlin 630 can mount an outboard up to 150 HP, so with our engine the performance is rather limited: even working with the trim, we didn’t get over 26 knots.