more than adequate
I own a 340 and have had plenty of opportunity to power through 8-10 ft. seas and wind>30. knt. The engine is a charm through all sorts of adverse conditions and tough docking situations.However, I would highly recommend a 3 blade feathering prop.It 's a difference of night and day. I have a Max Prop from PYI. Expensive, but is one of the most important pieces of equiptment I have on the boat. Yanmar puts on some engine courses that are highly recommended. The engine is a piece of cake to work on.