Grantmc: I have a
Bukh DV20 in my Cavalier 32. The manual says adjust the valve clearances every 200 hrs, so that's what I do. Unlike many boats, my
engine is very accessible so taking the valve cover off is a 1 minute job. Adjusting the valve clearances (there are only 4 on a 2 cylinder engine) is another 10 minutes. I recently bought a 14 year-old DV20 from another
boat in the marina. The
head gasket was blown,
water in the crankcase. When I removed the engine from the boat, I discovered that you couldn't actually
lift off the valve cover because the engine had been installed with not enough clearance under the bridge
deck. The only way to adjust the valves (or to replace the valve cover gasket) was to take the engine off its mounts and slide it forward 800mm!!!! This was done by a supposedly "professional" boat
builder. Obviously the valves had NEVER been adjusted in 14 years. Probably no other maintenance done except change the oil. I got $2,000 worth of spare
parts for $150.