Ask Sail: No-Go Engine
Jim Wilson of Heathsville, Virginia, asks:
My Catalina 40 has a Westerbeke 42B diesel engine with less than 800 hours. After a head-gasket repair, the engine was put back into the boat. Since then the engine dies when put into reverse while the boat is moving, apparently due to being “over-loaded.” It goes easily into reverse at the dock, but has no power. With the transmission out of gear, it revs easily. A diver checked the prop and bottom, and found no problems.
Nigel Calder replies:
First you need to determine if this is an engine or transmission problem. With the boat tied off at a dock, open up the engine compartment and have someone put the boat in forward and throttle it up. Look for the mechanism that moves the fuel rack on the engine to throttle up. Do the same in reverse. If the fuel rack goes through the same motion, then the problem is in the transmission. If, however, the fuel rack does not move, there’s a problem in the shift and throttle mechanism. I think you’ll find this is the culprit. If not, it sounds like your reverse gear is more or less seized up, but this is unlikely.