Yamaha 1984-93 115 HP Outboard Specs & Maintenance
Built from 1984 to 1993, this iconic 115 HP 2-stroke outboard is a legendary workhorse on the water. Featuring a robust 90-degree V4 block pushing 106 cubic inches (1730cc) of displacement, it delivers impressive hole-shot power and bulletproof reliability. Whether you are performing routine service or a full rebuild, our database provides the essential specs and mechanical insights DIYers need to keep this vintage 4-cylinder engine running strong.
Complete Technical Specifications
| Specification | Details |
|---|---|
| Model / Horsepower | 115 |
| Year Range | 1984-93 |
| Engine Type | 90 LV 2-st |
| Cylinders | 4 |
| Displacement | 106 cu-in (1730 mm) |
| Bore x Stroke | |
| Compression Ratio | |
| Full Throttle RPM | 4500-5500 |
| Idle Speed (Neutral) RPM | 700-800 |
| Idle Speed (Trolling) RPM | 600-700 |
| Spark Plug (NGK) | B8HS-10 |
| Spark Plug (Champion) | QL78C |
| Spark Plug Gap | 0.035-0.039 in (0.9-1.0 mm) |
| Ignition System | CDI |
| Ignition Timing (Idle) | 4-6 ATDC |
| Ignition Timing (Carb Pickup) | 3-5 ATDC |
| Ignition Timing (Full Advance) | 24-26 |
| 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) | 790 |
| Gear Oil Capacity (Oz) | 26.9 |
| Approximate Weight | |
| Battery CCA / Reserve | 380 (70) |
| Battery Reserve | 124 minutes |
| Tach Pole Setting | 12 |
| Test Propeller Part Number | YB-1624 |
| Test Propeller New Engine RPM | 4900-5100 |
Maintenance Summary
Keeping your 115 HP V4 tuned requires routine ignition maintenance. Always run fresh NGK B8HS-10 spark plugs gapped strictly between 0.035–0.039 inches (0.9–1.0 mm). Pair regular plug changes with fresh lower unit gear lube and proper fuel conditioning to ensure maximum 2-stroke longevity.
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Notice: Specifications, fuel ratios, and maintenance guidelines listed on VintageMotorSpecs.com are compiled for historical reference and educational purposes only.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.
Spot an error or discrepancy in these specs? Please contact us with your engine details so we can update our database.
Non-Affiliation Notice: VintageMotorSpecs.com is an independent historical reference database and is not affiliated, associated, authorized, endorsed by, or in any way officially connected with Outboard Marine Corporation (OMC), Mercury Marine, Yamaha, Honda, or any of their subsidiaries or affiliates. All product names, trademarks, and registered trademarks are property of their respective owners.