Replacement for Volvo MD1B

[Kyle2]

I think it is finally time to replace the old Volvo MD1B in my Snappie 747. The cylinder-head gasket has blown, and the mating surfaces of the block and head are both now damaged. The choice of replacement engine seems to be single-cylinder (Yanmar) or twin cylinder (Beta, Nanni etc). I think that a big advantage with the Yanmar is that it can be started manually, but also the twin-cylinder engines have an advantage in that they are fresh-water cooled. I think I have seen recommendations for all these engines on the forum before, but I wonder if anyone has replaced an MD1B and can recommend an engine, perhaps as an easy fit in the gap left by the Volvo, and suitable in terms of power and performance?

 

[retsina]

I had the single cylinder Yanmar and the 3 cylinder; they are very light and very good; however, it may be easier to repair your Volvo;

 

[PetiteFleur]

The two cyl. Beta Marine is available in 10, 14 and 16HP sizes - much better as it's fresh water cooled - the engine will last longer, it's smoother than the Yanmar 1cyl.

 

[Bilgediver]

One of my mates replaced the same with a Beta 14 hp and it seems an excellent engine...Very smooth but a lot lighter than the Volvo.

 

[roly_voya]

I replace an MD2B with a Beta. The main issue was the width of the sump, I had to move the engine beds out about 3". Well worth it as the new engine is much quieter, more powerful, lighter, uses less fuel and has better starter & alternator

 

[jwilson]

The Yanmar single-cyl engines "can" be handstarted but it is much more difficult than you'd expect for such a small engine. I've handstarted much bigger Volvos much more easily, probably because the Volvos had heavy flywheels.

 

[Bilgediver]

When replacing an MD 2 type engine with a Beta then specify their Atomic version. This usually takes care of the mountings and sump issue. You may need the smaller sump.

I would also specify the larger alternator and the high rise exhaust elbow.

 

[Stemar]

I changed the MD1 on my Snappy 24 a few years ago. I put in a VP2003 'cos it was available for the right price (free) when I needed it and I was seriously broke at the time. You don't need anything like a big unless you want to pretend you've got a McGregor, but try to be generous with the horsepower. Having an engine that can punch the tide into Portsmouth has transformed the enjoyment of the boat

The MD1's a heavy old lump - The 2003 and a dedicated starting battery weigh less than the MD1. The big issue is the length of the engine - I had to sacrifice part of the companionway step to get mine in, but if you're sensible in your choice, you shouldn't have a problem.

Expect to be able to keep your shaft, but with extra go you'll most likely need a bigger prop. My flexible coupling had been quite happy dealing with a 7hp engine that was producing more like 2hp for years, but the new engine was a bit of a shock to the system, and it wasn't long before it started complaining, then went on strike when I wanted to scurry out of the way of a cruise liner - just one of a number of times I've been glad of an outboard bracket on my transom!!