2GM vs 2GMF20

Mar 22, 2004
733
Hunter 30 Vero Beach
Can anyone tell me more about these two engines? Are the blocks generally the same? Are parts interchangeable?
 
May 24, 2004
470
Hunter 33.5 Portsmouth, RI
I belieive that 2GM is the SERIES of Yanmar engines. 2GM20F is a 2 Cylinder 18HP Fresh Water Cooled engine. The 20 is a rounding up of 18 HP, and F is for Fresh Water Cooled.

I have the 2GM20F engine in my 1990 Hunter 33.5 . (The following ear they realized that this engine underpowered that boat and changed to 3GM30F). The 2GM20F is a great engine - very dependable. Take care of it and it will love you for it.
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
I belieive that 2GM is the SERIES of Yanmar engines. 2GM20F is a 2 Cylinder 18HP Fresh Water Cooled engine. The 20 is a rounding up of 18 HP, and F is for Fresh Water Cooled.

I have the 2GM20F engine in my 1990 Hunter 33.5 . (The following ear they realized that this engine underpowered that boat and changed to 3GM30F). The 2GM20F is a great engine - very dependable. Take care of it and it will love you for it.
its one of the best little engines (even with its faults...water pump backwards and hard to get to oil dipstick) they have ever built
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
If the model ID does NOT have a "F" it is raw water cooled (sea water) rather than the closed loop "antifreeze" system.
 
Dec 14, 2003
1,434
Hunter 34 Lake of Two Mountains, QC, Can
If the model ID does NOT have a "F" it is raw water cooled (sea water) rather than the closed loop "antifreeze" system.
In which case it should also have anodes on the block wheras the F model does not.
 
May 24, 2004
7,178
CC 30 South Florida
The 2GM is an early version of the current 2GM20 engine. It displaces 586cc while the 2GM20 displaces 636cc. The 2GM is rated for 13hp at 3400 RPM and uses the KM2A gearbox while the 2GM20 uses the KM2C or KM2P gearbox. Do no know what parts could be interchangeable.