Yanmar's

[The_Sailing_Pelican]

Hi
I could swear I had a topic been develop on this subject but VOILA it's gone(?)...
So... I have on my Pearson 1985 a Yanmar 2GMF (13 hp) . Is this engine interchangeable with a 2gm20F(18hp)if so would the transmission be also, or do I have to bring in a new transmission for the 2gm20F?
Are the engine/transmission points of attachment on the boat floor engine compartment the same?
Ferl free to elaborate and explain in detail if you must(pls) since im new to this diesel Inboard stuff... Thx for taking the time and effort to make this contribution.

Thx again
C

 

[sail sfbay]

Welcome to the forum!!

Suggest getting a datasheet with specifications and installation manual for both engines to compare transmission models and dimensions as a start. The 2GMF20 transmission is a model KM2P 123 GM INBOARD.pdf (simplicity-marine.com).

 

[dlochner]

I can't answer your specific questions, however, based on the expensive tutorial on replacing and repairing transmissions over the past few months I can provide some basic knowledge.

Transmissions use standard SAE bolt patterns. Which particular pattern depends on the particular transmission and motor.

There are adapter plates that allow different SAE bolt patterns to mate with each other.

Gear ratios are important. You will want to match the gear ratio of the new transmission with that of the old as closely as possible. The new transmission may require a new prop pitch. When I replaced my transmission the prop had to be repitched.

Once you get all the parts, actually removing and replacing the transmission is pretty straight forward.

I worked with Fred Warner Marine and was pleased with their service. You might want to contact them for help especially if you are buying a new transmission from them.

Fredwarner Marine & Outdoors – Boating & Recreational Parts and Supplies

www.fredwarner.net

 

[Charlie98117]

I replaced my 3GMF with a 3GM30F. Perfect drop-in replacement, exact same engine mount spacing and location. Regarding the gearbox, the 2GM manual says it has either a KM2C or KM2P. The 2GM20F manual says it takes a KM2P gear. As noted above, there are different gear ratios that need to be maintained unless a prop change is included.