General Specifications
HP / kW
25 HP / 18.6 kW
Displacement
400 cc (24.4 cu in.)
Cylinders
2 (Inline)
WOT RPM
5000 - 6000
Weight
50 kg / 110 lbs
Drive & Lower Unit
Gear Ratio
1.92
Shaft Length
15", 20"
Electrical System
Alternator Output 60 Watts
Starting System Manual
Technical Maintenance Toolkit
Verified service specifications for the Mercury 25hp (2-Stroke) (1990)
Lubrication
Engine Oil
TC-W3 (50:1)
Gearcase Lube 260 ml
Ignition System
Spark Plug
NGK BP8H-N-10
Firing Order 1-2-3-4
Performance Specs
Idle RPM 700 ± 50
WOT Range 5000-6000
Alternator 60W
Standard Maintenance Intervals
20H Break-in Service
100H Annual Tune-up
300H Water Pump & Seals
Identification
The serial number for the Mercury 25hp (2-Stroke) is typically found on a plate located on the transom bracket.
Technical Toolkit
Maintenance Compatibility
These models share common service parts with the Mercury 25hp (2-Stroke):
Model Evolution
History of the Mercury 25HP series over the years:
Category Discovery
Reference Data
Information compiled from Mercury Marine factory service manuals and original sales literature published in 1990.