Yanmar Engine - GM/HM Series
Introduced in 1980 and 1981 this series was a completely new generation of engines. Lighter, smaller, smoother and quieter than previous engines. An F designation on the model number indicates factory fresh-water cooling. 35 AMP alternators. This series includes the following engines:
| Engine | HP | Years In Production | Comments |
| 1GM | 7.5 | 1980 - 1983 | Raw |
| 2GM | 15 | 1980 - 1983 | Raw |
| 2GMF | 15 | 1980 - 1983 | Fresh |
| 3GM | 22.5 | 1980 - 1983 | Raw |
| 3GMD | 22.5 | 1980 - 1983 | . |
| 3GMF | 22.5 | 1980 - 1983 | Fresh |
| 3HM | 30 | 1980 - 1983 | Raw |
| 3HMF | 30 | 1980 - 1983 | Fresh |