MD6B won't start ?

[crown28owner]

Been trying to start this engine for 6 months now any ideas what to
try next ?

Replaced broken injection pump last summer, this broke according to
mechanic from water in the fuel. I have carefully installed the pump
as per the manual, so the gears line up and the timing mark lines up.

The engine cranks normally, fuel comes out injection pump normally,
have had the injectors rebuilt, have of course changed the fuel and
filters etc, have checked the fuel going to injectors for air and
water and see nothing wrong. Have a fully charged marine battery so
she cranks at full speed. I have shot some quickstart into the air
intake a couple times (sputters for a couple seconds) and then
nothing.

I know very little about the engine internals but all worked fine
before the injection pump broke, the engine seems to have
compression, if I release the compression lever it hand cranks easy,
close lever then tough to crank manually, the valves seem to operate
fine (observing when hand cranking).

So I believe the fuel delivery part is all ok, don't know about
return lines if this could stop it from starting, or the exhaust
system if that could prevent starting.

What to try next , I bought some cetane booster and will put in the
tank and fuel filter this weekend and let her crank some more.

Any ideas anybody ?

Thanks
Kevin

 

[pfmarrack]

Kevin,
Here are my thoughts. I hope that someone will speak-up if I have
missed something.

Diesels need three things to run:
1. Fresh air.
2. Clean, dry fuel (at the right time)
3. Good compression.

If any of these are missing the engine will not start. I assume that
you don't have an intake obstruction and that from your description
you have compression and fuel to the injectors. That leaves timing
and fuel injection pressure. I don't know what happens if the
injector pump does not provide enough pressure to "pop" the
injectors. I assume that it would not start. The injector pump, just
being serviced should be fine. Could the timing of the injector pump
be out of phase with the engine (injecting fuel on the exhaust
stroke)?

Try this. Remove the air filter. Spray some WD-40 (I hesitate to use
quick-start, it's so volatile that you can get serious predetonation
in diesels and damage your engine) into the intake. Before you crank
the engine point a hair dryer blowing hot air at the intake. The
engine should try and start. You can keep it running by spraying
more WD-40 until the diesel catches. If the engine starts and
doesn't remain running I would think the problem is a fuel/fuel
timing issue.

Good Luck
Paul
V2926 "Overture"

 

[claudiomty]

Kevin
Paul is quite correct. Crank the engine and while it's cranking spray WD40
(most penetrating oils will work) into the intake and if the engine runs you
have compression and air. At that point that means your not getting fuel.
Even with the timing as wrong as it can be if the injection pump is working
it will spray fuel into the engine which will lay on the piston but still
detonate, only poorly. At full throttle it will barely idle and smoke like a
destroyer but it will run.

If your not getting smoke when cranking no fuel is present. I seriously
doubt if both injectors plugged or died at the same time. This leaves you
with either your primary pump is not pushing fuel up to the injection pump,
your sucking air somewhere between the tank and the primary pump, or your
pump is just plain not up to pressure to pop/spray the injectors.

Just for fun, open her up wide open (Tied off well beforehand) Crank and
spray and keep it running until the system self purges of any air and takes
off on diesel. While doing so look for a black cloud from the exhaist. If
your seeing smoke and she tries to run or barely runs your timing is
terribly off. If you dont see any smoke take the supply line off your pump
and crank again. If your getting diesel delivered to the injection pump then
tighten it back up and loosen both injector lines at the injectors. Give it
another whirl of say 30 seconds on the starter and see if it's pumping fuel
all over the head, if it is tighten the lines and it should start. If not
take it and a bad attitude back where they repaired it.

If you can pop an injector out without a fight do so and attach the
injection line just to see if it's spraying.

Hope that helps

Claude

 

[pfmarrack]

If you do remove the injectors and hook them back up to see if they
inject fuel, place them in a tin can to contain the spray. DO NOT
place any body parts near the injector when testing. The force of
the injected diesel will pierce the skin and diesel fuel is very
poisonous.

Paul

 

[wxt8981]

Hi
whatever you do (if the boat's in the water), close the
sea-cock for the water intake because all that cranking
will fill up the exhaust and eventually you'll get water
into the engine!
Wilhelm, V-257

 

[crown28owner]

Thanks folks

I took the wifes hair blower and the WD40 down on Sunday also armed
with my new book 'Be your own Marine Diesel Mechanic'. The WD40 did
not start the engine, however I realize now that I probably did this
wrong as I sprayed it in and then went up top to crank, whereas I
guess I should be spraying while I crank, so I'll try this again
tonight if necessary.

Now as far as the injectors go I did have those rebuilt and before I
put them back in I hand cranked the engine and they both popped just
fine and spray looked good....but...Sunday I discovered my big
blunder, I disconnected the fuel line from the injector and cranked
the engine while referencing my new book, I discovered the fuel was
injecting on the air intake stroke, no sooner was the fuel ejected
than the air intake valve opened. I had carefully (a couple times)
checked that the marks lined up on the gears at the back of the pump
so I was a little bit bewildered. I didn't much want to but I took
the flange off the cam gear cover down below(in about 2 feet of
space) it was then I noticed there was a different mark for each
gear, the '0' marks the cam gear, the '1' marks the injection pump
and a '2' marks another gear, I had lined up the injection pump with
the wrong mark on the intermidate gear so she was all off a complete
stroke.

I got everything put back together after a long long day...the
battery was almost gone at that point but I did see some smoke for
the first time in months, I'll try to start her again tonight on a
full charge...if she doesn't go I'll do the WD40 while cranking and
let you know.

Many thanks for all the help
Kevin

 

[crown28owner]

Wouldn't start last night so got out the hair blower and the new can
of WD40 (wide open on the throttle) and, yes she ran a couple times
for 10 or 15 seconds each time but would not go on it's own.

Afterwards disconnectd the fuel lines off the injectors and yes there
was fuel squirting out when I hand cranked, Pretty sure the timing is
okay now so I think I'll try and bypass the fuel tank and feed off a
jerry can to rule out some sort of contamination on the weekend.

Kevin

 

[crown28owner]

ok, thanks, yes she's in the water

I closed it off so I would'nt sink her somehow, but that's good
advice

thanks

 

[stevebirch2002]

Pilcher's Solent Bash 2006

(Friday 18th August - Sunday 20th August)Not only will we be having our usual fun and frivolity this year but
there will be a serious side to the weekend.

The famous Vega Solent Cup will once more be up for grabs. This cup has
been raced for since 1976 and has been won by some famous Vegas and
their owners, currently held by Roger Evill (Elkedor V1751). Predicted
Log Event over the same course for those unwilling, or unable, to race.
A copy of the rules will be supplied prior to the event.

Usual sailing rules (Fareham Sailing Club) will apply for the Vega
Solent Cup Race and the Portsmouth Yardstick will be used. The umpire's
decision will be final.

ASSEMBLE

Friday 18th Aug (HW 2003). Visiting Vegas to assemble at Haslar Marina.
Usual drinking, eating and yarning are compulsory. This is a wonderful
place to start the weekend.

Saturday 19th Aug (HW 0900). Both classes to assemble of Gilkicker Point
for a prompt start at 11:00.

Course: Gilkicker - Marlow Ropes Buoy (P) - Bob Kemp Buoy (P) - No Man's
Land Fort (S) - Bembridge Ledge Buoy (P) - Transit of Main Passage
(Submarine Bariier)

The Evening Event will be held at Fareham Sailing Club with a B-B-Q or
American Supper (everyone chips in). There is a dedicated B-B-Q area at
the club and plenty of berthing available. Some will be on fore and aft
moorings and some on spare pontoon berths at Salterns and the Clubhouse.
There is a wonderful bar with very cheap beer and a wonderful
atmosphere. The Prize-giving will be held during the evening for both
events. Remember to bring a prize donation if you are entering the
Predicted Log Event.

Sunday 20th Aug (HW 1015). Fleet disperses

Any takes please contact myself and I will pass on to Brian Pilcher.
Sounds like fun.

Steve Birch (Technical)