Joost, the raw water VP 2003 is quite a simple engine with a couple of problems that you should be aware of. There are no glow plugs so there is a cold start method for starting. Put the throttle in neutral and fully forward. Pull the engine stop out fully and return. This moves the rack beyond the full speed setting enabling each of the 3 injection pumps to over fuel the engine for starting. We sometimes need to give it a squirt of WD40 to help as well in really cold conditions.
The other problem is the gearbox splines can wear from "chatter" over time. There are a couple of well known fixes and todays price is likely to be £600.
That said Volvo made thousands of these engines and spares are readily available. Moody fitted the 2003 to the M31 Eclipse 33, the M336 and some M346. Marine Projects who made the yachts also build the Sigma range of yachts. Indeed the Sigmas have a very similar look inside. The Sigma 33 used a VP 2002, but the larger Sigma 36 a VP 2003 engine. Having sailed a 36 across the channel and back, I didn't notice any short comings. It was a training school yacht and did an awful lot of miles each year.
We tend to cruise at 2200 revs which is 5.5 knots, rarely taking it up to 2600 revs which is 6.5 knots. The red line is 3200 revs. I think Marine Projects must have bought a job lot of VP 2003s and put them in as many yachts as they could. If ours goes bang, then I would likely replace with another secondhand VP 2003 or a Beta 25. I don't think we need 28hp in a M31 and probably a good size for a M34/346. Since its only 3 cylinders you should have better access than say the Thornycroft engines which are 4 cylinders.
In the last 16 years we have replaced the engine mounts, alternator, thermostat and had the gearbox splines done. Not bad for a 35 year old engine.
So check the gearbox splines, the engine mounts for wear and its ability to start from cold. If it looks in good condition, with no leaks I wouldn't be worried.
Pete
