I recently completed the replacement of a Yanmar2GM20F with a Beta 20 in my 1993 Tartan 31. Thought I would share some of the experiance with anyone interested.
The reason for the replacement was not due to a failure by the Yanmar, it was primarily because I always felt the boat needed a bit more power and we are contemplating a trip down the Intercoastal. Also, I found a home for the Yanmar, so it was time for the swap.
The Beta 20 dimensions fore and aft are within an inch of the old Yanmar and that was a serious consideration as the engine on the Tartan is litterally installed in a box which serves as the companionway stairs.
Comparing the power curves on the two engines it seemed to be the right choice. After communicting with Stanley at Beta US I decided to go ahead with the project.
The following are the highlights of the work done to make the swap:
The engine beds were a good match for the standard Beta mounts but needed to be built up. This didn't surprise me as I don't think the original engie was ever properly aligned and should have been built up as well. I used 1 1/2" aluminum flat stock epoxied and screwed to the original beds. I then through bolted the new engine through the plate and the beds. This worked well and the alignment came right in.
I shifted the engine as far forward as I could because I wanted to use the flex coupling supplied with the new engine and needed room as there is little exposed shaft. I was able to get the space needed and still have clearance on the engine cover.
The hi Rise exhaust had to be modified to fit in the engine compartment. Basically I had to rotate it more to a port/stbd configuration to make it work in the space available. This was no big deal to me as I am a pipefitter, but could be done by anyone who has access to a shop that welds stainless.
The exhaust mod caused interferance with the air intake, but that turned out to be no issue as Stanley promptly provided me with a 90 degree intake ell for the air fillter.
The original shift linkage bracket would not work in the space available, but again Stanley had the fix with another bracket.
I kept the original 2 blade Flexofold prop (15X12) after contacting Flexofold for an opinion. They thought it would be the right match for the new engine. (Credit to them for not trying to sell me what I may not need).
I went with the "B" control panel with the optional recess mount available. That turned out to be a good fit as I only had to enlarge the opening a little. Looks like orininal equipment.
The rest of the job was pretty straight forward as far as hooking up fuel, cooling water, batteries, etc. I did opt to replace all hoses as part of the job. The exhaust is the same size as the old engine so I kept the original muffler and the fit up was easy.
Boat was launched last week. The engine ran beautifully, very smooth, plenty of power and quiet. Well worth the effort and glad I chose the Beta.
Feel free to ask if I can provide any further information.
I am attempting to attach some pictures of the job, but not sure if I succeeded!
