Water pump

I still had water in the oil so it was not backing up. Turned out to be the water pump. There are a couple of seals on the shaft that drives it that were letting water into the crankcase. I got a new water pump along with a VERY long list of other seals, gaskets and screws. The cover that the pump was on was very corroded from the saltwater leaking on it. The lower bolt was pretty much dust.

This is the lower bolt of the pump. The X is actually the hex nuts head. The survey said it had a higher than normal level of salt in the oil. So this had probably been leaking for quite a number of years.
One thing I did learn is that the lines going into the pump just pull out. There is a rubber seal there but it does not have a thread or anything to release it. It just pops out or in. Which is tricky since there are one on each side of the pump.


Gary Woods marine of Stuart was quite helpful in finding all the parts I would need and offering a few other good suggestions about how to do it. It was not too hard of a job and it seemed to have fixed the problem. We have run the motor from Stuart to Marathon and only sailed a few of those days and no sign of water in the oil.

Engine troubles

At the end of January we were planning on taking a trip down the coast. The boat was loaded up and ready to go but when I checked the oil in the engine it was milky looking. Water had gotten in there from somewhere. I changed the oil but the engine would not fire up. Had several people look at it but no one had any ideas nor did anyone have a compression gauge.

I finally bought a compression gauge and tested it. It was on the low end of what it should be but for a 25 year old engine that is not so bad. It should have been 284-355 with the starter but one cylinder was 280ish and the other 290.

Finally we got a nice day and I put a space heater in the engine compartment for about 3 hours. It surprised me by firing up almost immediately! I let it run for a few seconds and then stopped it as I had closed off the raw water intake. I opened that up and started it again let it run for about 20 minutes stopped it and checked the oil. It still looked new! I ran it a couple more times over the next few days and still no water in the oil.

I put some marvel mystery oil in the crankcase and put it in gear so the engine could get up to temp under load. Once I realized the thermostat was disconnected and fixed that the gauge went to where it should be. :)

So far the water problem looks like water backed up in the exhaust elbow from cranking it too much. I will change the oil again after I get the injectors cleaned and tuned. Right now it looks like the engine is working but hard to start in cold weather.

Things I have learned:
The specs say the Volvo Penta MD7B is 17 hp not 13 like the md7a. I don't know what else changed but all the manuals I found mostly referenced the md7a. Even the manual that came with the boat was for the md7a.

Even though I am in Florida a bit of extra heat on a diesel engine really helps a lot getting it started.

Getting a mechanic to look at a sailboat engine is hard. I only found one that would call me back and they wanted over $200 to compression test the engine. I bought a compression gauge for around $150 that I will likely never need again.