General Specifications
HP / kW
90 HP / 67.0 kW
Displacement
1526 cc (93.1 cu in.)
Cylinders
3 (Inline)
WOT RPM
5000 - 5500
Weight
109 kg / 240 lbs
Drive & Lower Unit
Gear Ratio
2.00:1
Shaft Length
20
Electrical System
Alternator Output 288 Watts
Starting System Electric
Technical Maintenance Toolkit
Verified service specifications for the Mercury 90 Inline (1998)
Lubrication
Engine Oil
TC-W3 (50:1)
Gearcase Lube 530 ml
Ignition System
Spark Plug
NGK BP8H-N-10
Gap Setting 0.040"
Firing Order 1-2-3-4
Performance Specs
Idle RPM 700 ± 50
WOT Range 5000-5500
Alternator 288W
Standard Maintenance Intervals
20H Break-in Service
100H Annual Tune-up
300H Water Pump & Seals
Identification
The serial number for the Mercury 90 Inline is typically found on a plate located on the transom bracket.
Technical Toolkit
Maintenance Compatibility
These models share common service parts with the Mercury 90 Inline:
Model Evolution
History of the Mercury 90HP series over the years:
Category Discovery
Reference Data
Information compiled from Mercury Marine factory service manuals and original sales literature published in 1998.