| I also have a single
cylinder Volvo diesel engine. In my case, an MD5A. It starts and runs
beautifully, but that wasn't always the case.
For the first few years of
ownership, I could spend five minutes or more trying to start the engine
and often flattened a battery doing so. Ultimately, the culprit turned out
to be a lack of compression caused by water getting into the cylinder on
the final stroke of the engine as I shut down. The water, of course,
washed the oil from the cylinder walls and the first few strokes of the
next startup wore the cylinder sleeve and piston rings to the point that
after a couple of years, I no longer had enough compression to start.
Since the engine has no glow plug and starts on compression alone, under
those circumstances, it simply didn't. I later learned that the original
3/1000th gap in the rings had widened to 1/8"!
In those days I wasn't as familiar
with boat systems as I am now and discovered too late that Ouyang had not
protected the cooling system with an anti syphon valve, nor was the wet
exhaust protected with a gooseneck fitting and thus water was given a
couple of routes to enter the engine. After having to remove the engine
for a complete overhaul, I installed both the anti syphon valve and a
Vetus gooseneck exhaust fitting and eliminated this problem. The only good
news in this scenario was that as opposed to most modern small diesel
engines, my Volvo came with a replaceable cylinder sleeve which saved the
added expense of replacing the entire block. Never-the-less, the overhaul
was still an expensive proposition.
Since that time, I have done two
more things which have greatly enhanced the engine's starting ability,
even in the coldest weather. Both have to do with eliminating as much of
the load as possible on the starter motor, thus enabling it to spin the
engine as fast as possible to create the compression necessary for
startup.
- Firstly, I have for the past 9
or 10 years used Mobil 1, a synthetic oil which doesn't thicken in the
cold and thereby reduces the drag on the engine. I also use the same
oil in the sail drive unit eliminating drive line drag which can be
significant considering that the unit will be at or very near the
temperature of the surrounding water.
- Secondly, I installed a 55 amp
Motorola alternator which basically freewheels until the engine
reaches approximately 1,000 RPM for the first time on startup, at
which point it automatically engages and begins to generate current.
It then continues to do so as required until the engine is shut down,
regardless of the RPM after that point. The effect is that there is no
drag on the engine from this source until the engine has started. That
drag can be significant with an alternator that tries to produce power
from the get-go, especially as your battery wears down while trying to
start. I have also installed two 27 group starting/deep cycle
batteries to provide ample juice.
Since making these changes, my
engine seldom takes more than a couple of seconds of cranking before it
fires, regardless of the season.
I hope this will be of some help to
other owners.
Martin Hunt
Escape 8.2 |
