Re-Powering A25 - Which Beta?

[cmoffatnc1]

Looks like we may give up the MD17 part chasing and look at a re-power. Has anyone gone with a Beta? If so, which Beta?

[DesertAlbin736]

We've only had experience with a 1986 vintage Yanmar 3GM30F which was a good engine for our early 1971 model . But from what I hear the Kubota based Beta engines are great. Size wise in terms of horsepower that depends on which variant of Albin 25 you have. If the earlier full displacement version with exhaust outlet on port side and the stepped engine box then the Beta 25/25 HP would be fine. That's a bit more powerful than the pre-1972 OEM 2 cylinder Albin AD21 engine and plenty to push to hull speed. If the later De Luxe semi-displacement variant with the aft section of the bottom flared and was originally equipped with the MD17 36 HP Volvo then the Beta 35 would be closer to the HP or the OEM MD17.

Here's a good buyer's guide article from Yachting Monthly magazine. IMO you can't go wrong with a Beta.

https://www.yachtingmonthly.com/gear/be ... uide-81530

[jerridsc]

Glad to see DA is still imparting his wisdom on this site.

[tribologist]

With a MD-17 I assume you have a De Luxe model. Most people put engines in the 35-40 hp range in them.

[A251975]

What experience do you want? My friends and I have opted for normal conversation at cruise and don’t worry about max speed. My boat-a deluxe with a Westerbeke 35B three…approx. 30 hp @ 3600. has a 17x14-4 blade with 2.72:1 ratio. 6.5kn @ 2200. Max 8. Friend has Westerbeke 38B four, maybe 35 hp @ 3600 with 17x12-4 blade, 2.47:1 ratio. Approx same 6.5 @ 2200, max 8.5. Have a friend’s ‘74 in my back yard with a nearly new Beta 35 (@ 2800) and 2:1 ratio with a 16x11-3 blade. Nearly finished refit; will test it this spring. I will be surprised if we don’t reprop it almost as soon as we drive it…I expect it will be obnoxious. BTW, a 4 blade prop made more difference in smoothness and ‘bite’ than we ever expected. Since the Beta is a 2800 rpm motor, I expect we will prop it for approx.2000 rpm cruise. At cruising speed you are using maybe 14hp…don’t need a big engine for that, but you want to generate that 14hp at a low enough rpm to be quiet; you can go too small and have it screaming. I think ideal would be about a 1.3L three or four cyl running at 2000-2200 rpm. Run as low (numerically high) a trans ratio as you can and as big a prop as you can. My suggestion would be a 3:1 ratio with a 17x15-4 blade. These engines are all cruising at about their torque peak so fuel efficiency is good and lugging not an issue; they all have been factory mated to 1800 rpm generators so full power at that rpm must not be an issue.

[DesertAlbin736]

That's interesting. Our boat being the earlier full displacement hull, we ran our 24 HP Yanmar 3GM30F at 2,350 RPM cruising at 6.5 kts turning a16.5" X 12 pitch prop. We did not have problems with noise or vibration since an owner previous to our immediate previous owner installed an AquaDrive thrust bearing/CV joint coupling system when the Yanmar was first installed in the late 1980s. We could easily hold normal conversations at cruising speed and hardly feel any vibration at all. Fuel burn rate was 0.4 to 0.5 GPH at 6.5 kts in calm water. So if there's room in the engine box I would reccomend looking into having one installed. All thrust of the prop is absorbed by the thust bearing which is bolted to the engine bed. The engine mounts are soft rubber and the CV joint allows some slight movement and/or misalignment similar to CV joints on front wheel drive cars. With soft motor mounts engine vibration is isolated from the hull.


See AquadriveUSA.com

[cmoffatnc1]

Thanks to everyone for this great input. Likely pulling the trigger on a Beta 35 for our DeLuxe.

[cmoffatnc1]

What experience do you want? My friends and I have opted for normal conversation at cruise and don’t worry about max speed. My boat-a deluxe with a Westerbeke 35B three…approx. 30 hp @ 3600. has a 17x14-4 blade with 2.72:1 ratio. 6.5kn @ 2200. Max 8. Friend has Westerbeke 38B four, maybe 35 hp @ 3600 with 17x12-4 blade, 2.47:1 ratio. Approx same 6.5 @ 2200, max 8.5. Have a friend’s ‘74 in my back yard with a nearly new Beta 35 (@ 2800) and 2:1 ratio with a 16x11-3 blade. Nearly finished refit; will test it this spring. I will be surprised if we don’t reprop it almost as soon as we drive it…I expect it will be obnoxious. BTW, a 4 blade prop made more difference in smoothness and ‘bite’ than we ever expected. Since the Beta is a 2800 rpm motor, I expect we will prop it for approx.2000 rpm cruise. At cruising speed you are using maybe 14hp…don’t need a big engine for that, but you want to generate that 14hp at a low enough rpm to be quiet; you can go too small and have it screaming. I think ideal would be about a 1.3L three or four cyl running at 2000-2200 rpm. Run as low (numerically high) a trans ratio as you can and as big a prop as you can. My suggestion would be a 3:1 ratio with a 17x15-4 blade. These engines are all cruising at about their torque peak so fuel efficiency is good and lugging not an issue; they all have been factory mated to 1800 rpm generators so full power at that rpm must not be an issue.

Could you share photos of the 35 in the boat? I am concerned about the fit. It would be most appreciated. Thank you.

[A251975]

I apologize in advance that I won’t be able to send photos for a while The boat is all bundled up for the winter…maybe April. An issue with most repowers from the Volvo Penta is that the VP trans drives off the front of the engine and the prop shaft is often a bit short when you move the new engine forward enough for the exhaust to clear, even with the optional Beta exhaust designed for VP repowers. Sometimes spacers and flex couplers will solve it; sometimes not. This Beta 35 install used a new prop shaft so the engine can sit fairly far forward for exhaust clearance. Width is mostly not an issue; height is ok also. The dipstick is a bit fwd., but reachable. Where the engine cover is inset to clear the fwd cabin door needed to be modified to clear the alternator. It is still very tight, but works as long as the engine house is clamped down and doesn’t shift. We’ve cut the engine cover horizontally into two pieces; not for clearance but for easier access by singlehander. Happy to answer any questions …till photos available.