Andrea Lynn had a good engine that I had hoped would last as long as I sailed her. But in the background I knew that the day would come that I would have to replace it. This year started off with a couple of fine sails. Then problems arose. First, it was not holding coolant at all. I filled it up and went on the sail, thinking it was a slow leak. On the return I started it up but discovered it had hydrolocking and was again out of coolant. After I got back to the dock I discovered oil in the water. At this point I knew the problems were serious.
Upon examination I discovered that the shaft seal on the fresh water pump was shot. I rigged the motor up to use raw water cooling and changed the oil several times trying to get rid of the water. It kept coming in. Finally I did a pressure test on the cooling system using a bicycle pump and a piece of hastily soldered copper pipe. Water came running out the air intake at about 5psi, confirming that there were serious problems.
Dave A and I proceeded to tear down the motor. In the process we discovered a warped head, blown head gasket, plenty of wear and rust. David K had noted a lot of blue exhaust when he saw Andrea Lynn underway with the motor running.
Dave A is a mechanic by livelyhood so he knows very well what he is talking about. He said that the engine could be rebuilt but there were a lot of ifs. Basically I would end up with a 35 year old unreliable engine for the cost of a rebuild. He recommended that I get a new engine. Other factors in the decision were the fact that the motor had been rebuilt once before in 1999 and the well known fact that Volvo Penta parts are very expensive or unavailable for the MD2B. Sometimes 3rd parties come in and make parts but these are not always made to the correct specifications. For example I had rebuilt the fresh water pump using such a 3rd party rebuild kit. It did not include the paper gasket or the shaft seals. I wanted an engine with good parts availability.
After some deliberation I decided to replace the engine.
The following details the steps I took.
We got everything together. Finally we started the motor to see if it would work. It cranked up for a few seconds and then was difficult to start. We made sure the fuel supply valves were open. Then we changed the Racor filter. Next we bled the engine by cracking the nuts on the injectors. Finally we opened the fuel return line. There was no fuel coming out of the hole. I found a flare connection on the fuel supply that was loose. I tightened it down quite a bit. We then got fuel from the return. We hooked the hose up.
Next the exhaust muffler was leaking a bit. I tightened the various parts of the muffler with an allen wrench. I also tightened the hose clamps for the exhaust.
During all that the starting battery died. I checked it with a volt meter. It showed a good voltage but the problem was a circuit break inside the battery. I switched the house and starting batteries. That was made much more difficult than it had to be because the wingnut would not come off. Dave pulled the bolt out of the plastic it was formed in. The upshot is that I need to get something like Zap Stop to protect the alternator.
Once we got past that the engine cranked fine and started. When we revved it up it developed fuel starvation issues. I fixed that by tightening the fuel supply flare nut some more.
We also looked for water coming out the back. After opening the valve just down stream from the raw water strainer it started coming out fine.
As you can see in the video this engine starts quickly - quite unlike the MD2B which liked to come up to speed at a relatively slow rate. Also this engine shuts down at once when one pulls the stop cable. In contrast the MD2B liked to coast down because of its heavy flywheel. I had to hold the stop cable for at least 5 seconds until it came to a complete stop. Also the new engine has much less vibration and is more of an even tone than the pulsing sound of the MD2B. Maybe it is less salty sounding but that is small potatoes. Early indications are that she'll run just fine.
It's really good to get familiar with the sounds. For instance when the fuel pump is pumping air it makes a chattering sound. If it is pumping fuel like it's supposed to it is much quieter. Also I can hear the fuel dripping from the return line back into the tank. If it drips more quietly then there is almost no fuel left. This engine self bleeds so the chattering sound would indicate bleading and its progress or show that there's an air leak in the fuel supply.
It's been 5 months from start to finish. This is the most complicated, hardest, most expensive and most time consuming boat project I have done. Would I do it again? Absolutely. I learned alot by doing this myself. I also gained an understanding of why boatyards charge so much to do this.
I give special thanks to all who helped in what ever way.