Yamaha 1988-93 150 HP Outboard Specs & Maintenance
Built for raw power and legendary reliability, the 1988-1993 150 HP 90° V6 two-stroke outboard remains a favorite among vintage marine enthusiasts. Packing a massive 158 cubic inch (2596 cc) 6-cylinder displacement, this workhorse delivers exceptional hole-shot performance and top-end speed. Whether you’re restoring a classic bass boat or maintaining a trusted cruiser, our technical database provides the essential specs, torque values, and maintenance guides you need to keep this 2-stroke powerhouse running strong.
Complete Technical Specifications
| Specification | Details |
|---|---|
| Model / Horsepower | 150 |
| Year Range | 1988-93 |
| Engine Type | 90 LV 2-st |
| Cylinders | 6 |
| Displacement | 158 cu-in (2596 cc) |
| Bore x Stroke | 3.54 x 2.68 in (90 x 68 mm) |
| Compression Ratio | |
| Full Throttle RPM | 4500-5500 |
| Idle Speed (Neutral) RPM | 675-725 |
| Idle Speed (Trolling) RPM | 550-600 |
| Spark Plug (NGK) | B8HS-10 |
| Spark Plug (Champion) | L78C |
| Spark Plug Gap | 0.035-0.039 in (0.9-1.0 mm) |
| Ignition System | |
| Ignition Timing (Idle) | 6-8 ATDC |
| Ignition Timing (Carb Pickup) | 5-7 ATDC |
| Ignition Timing (Full Advance) | 23-25 |
| Fuel System | Carb |
| Starting System | Electric |
| Oil Injection System | PB or 50:1 PM |
| Injection Oil Ratio | PB or 50:1 PM |
| Gear Oil Capacity (mL/cc) | 980 |
| Gear Oil Capacity (Oz) | 33.1 |
| Approximate Weight | 392-434 lbs (178-197 kg) |
| Battery CCA / Reserve | 380 (70) |
| Battery Reserve | 124 minutes |
| Tach Pole Setting | 12 |
| Test Propeller Part Number | YB-1626 |
| Test Propeller New Engine RPM | 4600-4800 |
Maintenance Summary
Keeping your 150 HP V6 running smooth requires regular care. Always inspect fuel lines, change lower unit lube annually, and install fresh NGK B8HS-10 spark plugs gapped precise to 0.035-0.039 inches (0.9-1.0 mm). Proper tuning ensures optimal combustion across all six cylinders.
Disclaimer & Information Notice: Specifications, fuel ratios, and maintenance guidelines listed on VintageMotorSpecs.com are compiled for historical reference and educational purposes only. Always verify data against an official OEM service manual prior to ordering parts or executing repairs. VintageMotorSpecs.com assumes no liability for repair errors, equipment damage, or personal injury resulting from the use of this data.
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