MD6A runs for ten minutes then quits

Oct 30, 2019
80
I just bought Albin Vega 2141.The boat was on the hard and the
owner got it running. We sucked water from buckets for cooling. The
motor ran fine for 15 or 20 minutes. One week later we put the boat
in the water and it was hard starting. We operated the lift pump
manually and bled off a little air at the fine filter. The motor
started, came up to temperature and ran for twenty minutes or more.
We motored over to the fuel dock and shut the motor down and filled
up. We put in just over 5 gallons in a ten gallon tank. We started
the motor to leave and when we were backing away from the fuel dock
it quit, and the best it will run is for almost ten minutes, and then
it quits again. Here is what we've done and found out: We eliminated
my fuel tank and fittings by hooking up an external tank; no luck. We
have bled everything to the injectors and when it quits we do not
find air. We have have replaced banjo gaskets everywhere, and have a
clear return line fron the injectors to the fine filter. The lift
pump is operating fine, and to check it we supplied fuel pressure to
the engine with an electric pump; no luck. The exhaust "appears" ok
when its running. We disassembled what we could and found no clogs. I
have not ruled out an exhaust system entirely. In fact I haven't
ruled anything out entirely yet. But there is one thing I find
suspicious. The fuel return line from the injection pump is not
returning fuel to the tank. We unhooked the line and when the motor
runs for ten minutes no fuel returns from the injection pump to the
tank. We talked to Paul B. (can't recall his last name right now) the
diesel mechanic at the Brewer Yacht Yard in Mystic,CT and he said
that fuel does not always return to the tank from the injection pump
on the MD6A. Does anyone have an idea here? The only other suspicious
thing I ran accross in some paperwork here at home is that the
decompression lever can sometime be incapable of dropping down far
enough to cause compression. A light kind of came on when I ran
accross that little tidbit. The boat is three hours away and I'm
stuck at that marina until I get the motor running or buy an
outboard. On the light side I considered calling Sea Tow and telling
them I was stranded at the pier and could the come tow me out into
the middle of Long Island Sound. Any ideas asap would be GREATLY
appreciated. Thanks to everyone.
 
Oct 31, 2019
24
I probably just missed seeing it in your post, but did you replace the fuel
filter. If not, it may be partially clogged and the engine is fuel starved.
I don?t think it would be the decompression lever, if that was the problem
the engine would not run at all.
Robert Gainer
 
Oct 30, 2019
80
Thank you for the reply, Robert. The filter has been changed and pumped
full of fuel and bled of air with the lift pump. The lift pump screen is
clean. Fuel is flowing into the injection pump. With the lines to the
injectors disconnected at the injection pump the pump squirts fuel in time
with the pistons. Whether its pumping enough or strong enough, I don,t know.
However when the motor runs, it runs well. But it does appear to starve of
fuel and die. Thanks again.
 
Feb 6, 2011
253
Have you checked to see if anything is blocking the fuel tank vent or vent
line? If it is blocked, the pump will try to draw a vacuum on the tank - which
it cannot do. The time is just about right for that, too.

Good Luck.

Ed Davis aka saylered@... in Mystic, CT
 
Dec 18, 2001
31
I'm sure this isn't a great help, but I can assure you from bitter
experience that on my MD6A (V1775) when running, a high proportion of fuel
appears to be recirculated back to the tank.
I once ran the engine from a slave tank but forgot about the return line -
it took a little time to realise why fuel consumption had rocketed to about
five gallons an hour!

Best regards
Frank Fowler, 'Alkira', Liverpool.