General Specifications
HP / kW
50 HP / 37.3 kW
Displacement
721 cc (44.0 cu in.)
Cylinders
4 (Inline)
WOT RPM
4500 - 5500
Weight
75 kg / 165 lbs
Drive & Lower Unit
Gear Ratio
2.0
Shaft Length
15", 20"
Electrical System
Alternator Output 113 Watts
Starting System Electric
Technical Maintenance Toolkit
Verified service specifications for the Mercury 50hp (Inline-4) (1975)
Lubrication
Engine Oil
TC-W3 2-Stroke
Gearcase Lube 440 ml
Ignition System
Spark Plug
NGK BUHW (Surface Gap)
Firing Order 1-2-3-4
Performance Specs
Idle RPM 700 ± 50
WOT Range 4500-5500
Alternator 113W
Standard Maintenance Intervals
20H Break-in Service
100H Annual Tune-up
300H Water Pump & Seals
Identification
The serial number for the Mercury 50hp (Inline-4) is typically found on a plate located on the transom bracket.
Technical Toolkit
Maintenance Compatibility
These models share common service parts with the Mercury 50hp (Inline-4):
Model Evolution
History of the Mercury 50HP series over the years:
Category Discovery
Reference Data
Information compiled from Mercury Marine factory service manuals and original sales literature published in 1975.