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Discussion Starter #1 (Edited)
**Atomic Four A4 to Yanmar 2GM**--Trying to repower my Islander 29's A4 with a used Yanmar 2GM. Would love to see or get pics of necessary engine bed modifications. Especially interested in the actual needed changes in width, height and angle as well as needed clearances for pan since the Yanmar mounts will need to be further apart and the A4 trans flange is a different height compared to Yanmar. Already removed and disposed of the Atomic Four, but would like to use what I can of the old engine bed timbers (sister if possible?). Since I am starting from scratch and trying to do the engine installation while boat is afloat, would like actual measurements from a similar installation so I can get close before I have to do shaft alignment, thus saving megawork and time. If anyone knows of an Islander 29 (or similar boat-older Columbia, Pearson, etc?) with a Yanmar 2GM installed, please refer them to me or pass along an email address. Am in SF Bay area, but pics from afar would be greatly appreciated! Also looking for tips on removing the old cutlass bearing (know that I will have to haul for this). Many thanx!
 

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Try an google image search for both engines.. you're likely to get drawings from manuals that have been published on line... and then compare the footprints to give you an idea.

Years back we removed an Atomic2 (yes, 2 - not a typo) and dropped in a new Volvo 2001.. the mount spacing was almost 4 inches narrower than the existing beds. We through-bolted (to the original beds) aluminum angle iron to narrow up and match the mounting angle difference.
 

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Discussion Starter #4 (Edited)
Thank you both for the replies so far. I already have my Yanmar 2GMF and am looking for anyone who has done a swap with that engine for the Atomic A4 so that I can get firsthand info and pics from someone who has done this particular substitution. Am looking for the exact changes to the existing A4 engine bed needed to accomodate the Yanmar......length, width, height, angle (any changes needed to fit the Yanmar engine mounts and meet the shaft coupling).
 

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Discussion Starter #6
For info to others about repowering from an Atomic 4 to a Yanmar 2GM or 2GM20, refer to the Plastic Classic Forum article by Ray D. Chang who gives a blow by blow description with photos of his Triton 106. Extremely helpful. He started his posts Feb 03, 2012. You can easily download the entire project.
 

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Discussion Starter #7
Re: ISLANDER 29 repower with YANMAR 2GM? (Atomic 4 to Yanmar)

Please refer to my earlier post if you are looking for info on changing out an Atomic A4 and replacing with a Yanmar 2GM or 2GM20 for article and pics of this project. Will clarify any questions you might have. Good luck and good sailing!
 
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