Mariner and Mercury now have new electronically fuel injected (EFI) four-strokes rated at 80hp (58.8kW) and 100hp (73.5kW).

These are in-line four cylinder engines displacing 1,596cc and with a maximum rpm in the 4,500 to 5,000 range for the 80hp and at 5,000 to 6,000 for the 100hp. They include water-cooling, CDI ignition, electric starting, four-valve dual overhead cam induction, remote steering with optional tiller kit, 20 amp alternator, power trim, overheating warning system, pressurised wet sump lubrication and through-prop exhaust. Dry weight is 175kg. Shaft length is Long (508mm).

The EFI system uses a single mechanical fuel pump that lifts petrol to the engine vapour separator. It then provides a steady supply of pressurised fuel for the fuel rail. All Mariner and Mercury four-strokes from 25hp (18.4kW) upwards are now electronically fuel injected.

Ease of starting is the biggest single advantage of EFI, usually requiring only a single turn of the key and no choke, regardless of environmental conditions. A further benefit is smooth throttle response, without the lagging associated with carburetted outboards. EFI engines are more responsive throughout the rpm operating range.
Fuel metering by the on-board microprocessor distributes precisely the optimum amount of fuel at any time, maintaining a high degree of efficiency and reducing fuel costs.

Both the 80hp and 100hp EFI four-strokes meet all European emissions requirements.