Yamaha Marine - Four Stroke Series
| F20hp | F15hp | F9.9hp | F8hp | F6hp | F4hp | F2.5hp | |
| Engine Type | 2 cyl. | 2 cyl. | 2 Cyl. | 2 Cyl. | 2 cyl. | 1 cyl. | 1 cyl. |
| Displacement | 22.1 ci (362 cc) | 22.1 ci (362 cc) | 12.9 ci (212 cc) | 12.0 ci (197 cc) | 12.0 ci (197 cc) | 6.7 ci (112 cc) | 4.4 ci (72 cc) |
| RPM Range | 5000-6000 | 5000-6000 | 5000-6000 | 5000-6000 | 4500-5500 | 4000-5000 | 5250-5750 |
| Alternator Output @ W.O.T. | 10A | 10A | 6A ** | 6A ** | 6A ** | N.A. | N.A. |
| Compression Ratio | 9.3:1 | 9.3:1 | 9.5:1 | 8.8:1 | 8.8:1 | 8.4:1 | 9.0:1 |
| Fuel/Induction System | SOHC | SOHC | SOHC | SOHC | SOHC | OHV | OHV |
| Lubrication | Wet Sump | Wet Sump | Wet Sump | Wet Sump | Wet Sump | Splash | Splash |
| Ignition System | CDI Micro Computer | CDI Micro Computer | CDI Micro Computer | CDI Micro Computer | CDI Micro Computer | TCI | TCI |
| Starting System | Manual or Electric | Manual or Electric | Manual or Electric | Manual | Manual | Manual | Manual |
| Shaft Length | 15 in., 20 in. | 15 in., 20 in. | 15 in., 20 in. | 15 in., 20 in. | 15 in., 20 in. | 15 in., 20 in. | 15 in. |
| Gear Ratio | 13:27 (2.08) | 13:27 (2.08) | 13:27 (2.08) | 13:27 (2.08) | 13:27 (2.08) | 13:27 (2.08) | 13:27 (2.08) |
| C.A.R.B. Rating | 3-Star | 3-Star | 3-Star | 3-Star | 3-Star | 2-Star | 2-Star |
| Weight* | 114 lb (52 kg) | 114 lb (52 kg) | 91 lb (41 kg) | 83 lb (38 kg) | 83 lb (38 kg) | 48 lb (22 kg) | 37 lb (17 kg) |
| Warranty | 3 Year Limited Pleasure Boat - 1 Year Limited Commercial | 3 Year Limited Pleasure Boat - 1 Year Limited Commercial | 3 Year Limited Pleasure Boat - 1 Year Limited Commercial | 3 Year Limited Pleasure Boat - 1 Year Limited Commercial | 3 Year Limited Pleasure Boat - 1 Year Limited Commercial | 3 Year Limited Pleasure Boat - 1 Year Limited Commercial | 3 Year Limited Pleasure Boat - 1 Year Limited Commercial |
* Weight refers to shortest shaft length available.
** Consult your dealer for optional equipment.