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-   -   Lauralee: Here''s your fix. (http://www.sailnet.com/forums/gear-maintenance/7908-lauralee-heres-your-fix.html)

VIEXILE 09-01-2003 07:46 AM

Lauralee: Here''''s your fix.
 
I figgered it''d be quicker to put this at the top of the list rather than have you go looking for it:
O.K. I''ve sat for hours staring at my MD2B with manual in hand and found it mechanically simple all the way around (notwithstanding transmission repairs). I''ll bet my dinghy I could start that motor and keep it running.
1.) Change out all fuel lines with AYBC approved lines. If you''re sure everything is cool, then don''t.
2.) Using a foot pump (air mattress inflation pump) on the fill schnozzel to the fuel tank, with a little rubber elec. tape wrapped around to seal the fill hole, set up the pump (to blow, not suck).
3.) Two person job. There are two bleed screws on the back of the engine. One near the cold start button and one on the fine fuel filter. See manual. Use a box end wrench on the former, and, necessarily, a screwdriver on the latter. Back both out far enough to allow fuel to flow out of each. Don''t DROP these little &*(# ers. Don''t take them out all the way.
4.) Have person one start pumping air into the tank. Even though it''s vented, the vent can''t blow out air harder than you pump it in. KEEP PUMPING.
5.) The person with the (er 10mm?) wrench and screwdriver watches the bleed screws until no more bubbles or air comes out.
6.) Close the filter bleed screw (on top of the fine filter) when fuel runs clear first. It''s the first bleed screw in the fuel system. (As a side note, that rubber gasket at the top of the fine filter CAN leak if it isn''t seated correctly). KEEP PUMPING.
7.) Go to the bleed screw near the cold start button. KEEP PUMPING. When clear fuel is running, no air or bubbles, close it on the downstroke of a pump by the other person in the cockpit.

The problem is, I don''t believe the little hand lift pump in the fuel pump works well at all, and it won''t push the fuel all the way through to the injectors. EVERY YEAR I go through this with my MD2B and it holds for the balance of the season. I believe just once over the past 10 years it cut out due to lack of fuel. What''s happening is you''re getting just enough fuel to the injectors for them to run for just long enough to burn it, then air shows up in the system. Every year I change my racor and other filters, reseal everything and go through the pumping process. I can now do it alone. What it does is fill every possible void in the system with fuel up to the injectors. I''ve never pulled my injector lines to bleed it. You don''t have to. Never seen anyone else do it this way, but had a mechanic watching me one day say "good idea." Such is the result of starting from scratch with systems, with no preconceived notions, and figuring them out yourself. The rebuild on the engine, including new big end bearings on the shaft, is easy, but time consuming. I''ve taken the engine down to the shaft, collected all the parts and rebuilt it all the way up through. No mechanical experience. That was in 1998 and she still runs fine. Send me an address for my invoice.

VIEXILE 09-01-2003 07:53 AM

Lauralee: Here''''s your fix.
 
Oh yeah. Sometimes it doesn''t take on the first try. Go back, repump, rebleed (no air bubbles, clear diesel running out of the screws) and do it again. Seems as though I''ve had to try it up to three times in the past to get it to take. Sitting over the winter, the fuel must drain to low points somewhat, introducing air into the system. The trick is clear fuel only from the bleed screws. Another thing I do is NEVER leave the dock, anchor, or mooring without running the engine up for at least 3 or 4 minutes - just in case. It only happened once that it cut out, but there were 25 or 30 Hinckleys all around me in SW Harbor and it was blowing. Bad scene, but foot pump and bleed screws fixed it in record time. KW

VIEXILE 09-01-2003 08:00 AM

Lauralee: Here''''s your fix.
 
Now if that damn Hurricane Fabian would turn north like they "say" it''s going to. 400 miles away. Time to head for KMart. KW

lauralee 09-01-2003 04:40 PM

Lauralee: Here''''s your fix.
 
Viexile,

Thanks! I like the sound of this procedure. I haven''t been comfortable that I was getting all the air out of the lines, but I didn''t know what more to try. I will try it out this weekend. I really appreciate you taking the time to write this out. I''ll let you know how it turns out.


AJS 09-02-2003 05:22 AM

Lauralee: Here''''s your fix.
 
For God''s sake people! Of course you have to bleed the injector lines, and no, the lift pump will not do it, its not meant to. It only supplies fuel to the injector pump so that it can then pump fuel at very high pressure and low volume through the injector lines to the injectors, where the pressure overcomes the spring in the injector and fuel mist is squirted into the combustion chamber. This is why the injector lines are made of steel.
To bleed: first bleed the low pressure side of the system using the lift pump or the incredibly complicated and unnecessary method described above. Once you have clear fuel with no bubbles flowing to the injector pump, crack the fitting on the end of one injector line at the injector and crank the engine with the decompression lever pulled so that it will roll over easily and not start, make sure the thottle is on a little. Roll the engine over until you see little squirts of fuel coming out of the fitting. Tighted the fitting while the engine is still rolling over. Now do the other injector. Engine should now start and run. Rolling the engine over is the only way to make the injector pump operate and push clear fuel through the line. If there is air this line the air compresses instead of the injector spring and exactly nothing happens. It sounds like you''ve missed this last crucial step. This is very common and must be done to every diesel I''ve ever seen that has been run out of fuel. I can''t believe it hasn''t been mentioned already.
Be careful not to get tangled up in the flywheel or other rotating parts while doing this.
Also, if you find that the lift pump is barely working when pumping by hand, rotate the engine a little and try again. The lift pump is operating by a rotating cam. If the node on the cam has the lift pump fully compressed then it won''t work when you try pumping by hand. Rotating the flywheel a partial turn will remedy this.

ajs

VIEXILE 09-02-2003 02:10 PM

Lauralee: Here''''s your fix.
 
Like I said, it''s worked every year, and all the system voids get filled without putting fuel all over the engine. Haven''t cracked the lines yet except to put new tips on the injectors. That''s what the two bleed screws on the back of the engine are for. Nothing in the manual about cracking the injector lines, although the manual perceives someone turning over the engine, which, given the foregoing flywheel warning, and it IS a beast of a flywheel, ain''t my idea of a good time when you''re hanging over it trying to reach the bleed screws. Can''t see much complicated about pumping a foot pump and closing two screws. I''d hate to think about loosening injector lines and retightening them while drifting around when I''ve got a quick fix that doesn''t require turning the engine over. I HAVE cracked the injectors on other motors, Perkins, Yanmar, but simply pressurizing this one and using the bleed screws seems to work just fine. Matter of fact, I just fired the thing in Maine after 2 years on hard prepping it for transport down to the Carib. 1 shot of pumping and bleeding and she purred like a . . . well, not a kitten anyway. KW

fourknots 09-03-2003 07:20 AM

Lauralee: Here''''s your fix.
 
AJS is right. I owned an MD2B for years, and after every fuel filter change, that''s what I did.

I you have a hand start crank (and you need one, since one of the beauties of these engines is their ability to start by hand) you can use that to bleed if you''re not comfortable with the starter. Just make sure you tighten the injector BEFORE you stop cranking or else air may get back in the system.

If the engine starts, but quits, bleed it again - sometimes you don''t get all the air out. if it still quits, you may have a leak letting air into the system. If you bleed it again and there''s more air bubbles, it''s probably a leak.

h37skipper 09-03-2003 07:59 AM

Lauralee: Here''''s your fix.
 
Still too hard. I use a 3 gal. Tempo tank with the outboard engine connector cut off. I remove the inlet hose to the Racor filter and clamp on the tank hose. A few squeezes of the hose bulb and she starts right up, no bleeding necessary. Now reconnect the fuel line to the Racor and she will start and run. If you have locker space the Tempo is nice insurance if(when) you have fuel problems.

VIEXILE 09-04-2003 06:22 AM

Lauralee: Here''''s your fix.
 
I LIKE that one. When I rationalized the foot pump, it''s all I had available. With the hand pump, I can lean over the engine and close both screws without any help. Kewl.

AJS 09-04-2003 10:09 AM

Lauralee: Here''''s your fix.
 
There WILL come a time when you''ll have to bleed the injector lines. Doing it from the low pressure side simply won''t work.
If air gets into these lines the only way to get it out is to bleed them. You can''t force it throught the injectors with any kind of air pump.
Of course, its nice to just keep the air out of these lines in the first place.
AJS


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