I have done extensive repairs and upgrades to my boat (hull #77). I think it is a wonderful boat, sails amazingly fast for 35 years old, especially in light air. People on newer boats are amazed. And they always say how pretty she is. Since the water on the West Coast of Florida is very thin in most places, this is the perfect boat for me and the way I want to sail. I ain't gonna cross any oceans, but I love to gunkhole, for which this boat is perfect. Which is also why I own her and spend lavish mounts of time and money on her. I hate most of the new boats. They sail fairly well, but are ugly and built paper-thin. Unlike ours, which are built like bridges. Except for a few things like the hull-deck joint, probability of soft decks in certain areas, etc. But overall, I love my boat. The 27-hp Yanmar is the 3GM30. It is a good engine. The one that had been installed in my boat was the 3HM35, which was much too big. Actually, I think the 3GM30 is a bit large for the C-31. You won't use most of its power. The 20-hp Beta is fine for the 8500 pounds this boat displaces, plus it is LOTS cheaper than a 3GM30. The 3HM35 had a gear ratio of almost 3:1, so that the propeller was only turning at about 1200 RPM when the engine was running at 3400 RPM. This would have been fine if I could have hooked it up to a 18"-20" diameter propeller. Unfortunaetly, the largest propeller that would fit in the aperture was 12". The 12x12 three-blade prop, turning at only 1200 RPM, would not develop enough thrust to move the boat faster than about 2 knots in calm water. To make matters worse, I think the engine would overheat and shut down because it was working too hard. So I was glad when I got the Beta Marine 720 installed and running. As I mentioned earlier, it was cheaper, liighter, quieter and smoother than the Yanmar. It has been a wonderful addition to my boat and has restored my wife's confidence in it. She refused to go out in the boat until it had a working engine.
The engine has 3 cylinders, which makes it smoother than the 2GM20. I ground out parts of the aoperture a but so I could fit a 13-inch prop. The one on there now is a 13x12 two-blade Teignbeigh from England. The guy from general Propellor in Bradenton recommended it. The gear ratio is 2:1 and this combination moves the boat at 6 knots with the engine not working too hard, maybe 2700 RPM (when the bottom and the prop are clean, which they are not now).
Several people have requested information on the same subject. Rather than re-type it, I will find one of my replies and forward it to you.
Here it is:
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The Beta Marine engine has been a real gem and the best thing that happened to Sandeeling in 35 years (other than me buying her). It is rated at 20 hp, 18 continuous, has 3 cylinders and is lighter, smoother and quieter than the Yanmar 2GM20 or the 3GM30. I think it was also about $1600 cheaper than the 2GM20. Beta Marine did a very good job with the marinization of the Kubota Diesel. I would say it is first class. It even has a cute little brass pump mounted on it to change the oil.
One reason I went with that engine instead of a Yanmar is because ot the distributors, Beta Marine of NC., Stanley Feigenbaum and Richard Girard. I think they are located inside a truck and farm equipment distributorship. Which is o.k. because the Kubota is well-known for its use in pumps, generators and compressors.
Sure,Yanmar and Mastry (the major Yanmar distributor) are the big shots in the small Diesel department, but my experience with both Yanmar andMastry were decidedly unfavorable. They just got too big for their britches to care for a lowly customer such as me. My engine (3HM35) had come out of another boat and since I was not going to buy a new one from them, they had no interest in helping me.
When I contacted the Beta Marine guys, it was like a breath of fresh air. Unlike Mastry, they seemed genuinely interested in me, my boat and the problems I'd been having. They were very open and approachable, taking lots of time to answer my questions and send any information I needed.
The problems I encountered had nothing to do with the Beta or the distributoirs. They were caused by the jerk who installed it. Richard and Stanley were looking for reputable people to install Betas in Florida, hadn't gotten anybody in the west coast of Florida yet. I found somebody who I thought would do a good job, but he screwed me royally. When you choose an installer or mechanic, check his references and ask to see examples of his work and talk to the owners of those boats. I spoke to one powerboat owner who had an engine installed by this guy and seemed happy with the job. I shoulda checked further. We agreed in advance that the installation would cost around $2000, plus or minus. Right. He said was a good Diesel mechanic, but it soon became clear that he knew nothing about sailboats. After $2700, he still hadn't finished the job and did some things absolutely wrong. I had to fix some of those things myself and got another mechanic to finish the installation, which cost an additional $500. I shoulda gone with the second guy first. It would have only cost me $1500.
But everything is fine now. The engine has never failed to start within 2 seconds of turning the key (except today, when the battery terminals were corroded. Cleaned and greased them and she fired right up).ANd it moves the boat faster at idle than the Yanmar ever did working hard. (This was due to a mismatxh between the engine, transmission, prop and boat. The 3HM35 was basically a good engine, but too big and not geared for my boat, noisy and a bit rough-running.)
During the Beta installation, I had a problem with getting the output shaft coupling to match up with the one on the propeller shaft. Richard sent me a coupling Fed Ex. That one didn't fit either and he Fed Ex'ed me ANOTHER one the next day which fit. THAT'S good customer service!
So parts are available. The fact that Kubotas are used world-wide, and that Beta Marine has dealers worldwide should make parts available wherever you may sail.
I saw Richard and Stanley at the St. Pete Boat Show and they seemed really glad to meet me. They remembered immediately who I was (after a year) and were glad to hear that my engine was performing as expected.
SO, finally answering your questions, I would not hesitate to recommend the Beta Marine engine or Beta Marine of NC. I think they are both superior in their field.