Yanmar engine swap

[bigmac91]

Thinking of changing a 1gm10 to the gm20 in a Hunter 27, anybody know if the mountings are the same dimensions and any other issues I may come across.

Thanks

Les

 

[prv]

Kindred Spirit had had the same conversion before we bought her.

Judging by the old bolt holes, the feet had to be moved but the bearers underneath stayed the same. The new engine was also a very tight fit in its box - I assume you've checked and you do have the space?

We also had a dirty great lump of lead in the bow to counteract the increased weight aft.

Pete

 

[Tranona]

The distance between beds is the same but for obvious reasons the fore and aft dimensions are greater. You need to get the installation drawings to see what the extra length is and whether your beds are long enough. If you want to keep the same stern gear you will have to accommodate the extra length forward, but if there is room to shorten the shaft you may be able to share the additional length.

An alternative for a substantial increase in power for a lot less money is to fit a Nanni/Beta 14 which has virtually the same footprint as the 1GM and a very straightforward replacement. 1GMs fetch good money in working order so should keep your cost to around £3k net.

 

[30boat]

 

[bigmac91]

The distance between beds is the same but for obvious reasons the fore and aft dimensions are greater. You need to get the installation drawings to see what the extra length is and whether your beds are long enough. If you want to keep the same stern gear you will have to accommodate the extra length forward, but if there is room to shorten the shaft you may be able to share the additional length.

An alternative for a substantial increase in power for a lot less money is to fit a Nanni/Beta 14 which has virtually the same footprint as the 1GM and a very straightforward replacement. 1GMs fetch good money in working order so should keep your cost to around £3k net.

Thanks lads, I have seen the plans for both engines online and the main consideration is going to be length . I know the Nanni engine well as it's in my other boat and is a great little engine. (Other boat is a Van de Stadt Legend 29, currently up for sale ).
The Hunter is not yet in the water so I will see how the engine copes with the tides on the northeast coast before going for a change.

Thanks again

 

[Topcat47]

The OEM engine mounts for the 1GM10 and the 2GM20 are not the same, although physically they are interchangeable. I think the engines are supplied with mountings if bought new. Check with Marine Power at Bursledon. If the definitive answer isn't on the website, they'll tell you over the phone.

 

[prv]

I have a set of 2GM20 engine mounts in my shed; removed as a precaution since we had the engine out anyway, but really nothing wrong with them and not all that old either. Let me know if you're interested in buying them.

Pete