How do I match an old engine to a new engine for my boat?

Question

I have a 1975 Volvo Md6A.

Answer 1

Beta Marine is providing marine engine packages for repowering Volvo engined boats. Their Beta 10 engine offers about 10% more power than your Md6A, with the same fuel consumption. because of a better power curve. They can supply engine mounts and lower drive options, or a "bobtail" conversion package, if your lower unit is good. http://www.betamarinenw.com/Engines/Beta...

If you want more power, the convenience of electric start, a sealed cooling system's improved reliability, and the option for taking off more electrical  power for your cabin, you might look into something like the Yanmar 2YM15 or 3YM20. If you motor a lot, or are in and out of inlets at tide change, you'll appreciate the smoothness of the 3 cylinder design. http://www.yanmar.com.au/marine/gm_serie...

In the end, it's always a compromise of budget, fuel consumption, and what the hull needs and can take, isn't it? It's good to get down to boatyards in your area, and see what other people are doing with their repower projects.