Need help on bleeding a Yanmar 2GM

[PBzeer]

Was motoring along, when suddenly the engine starts losing revs, and then dies. I figured I finally had a clogged filter. After changing it though, I can't seem to get the line bled. Thought I understood what to do, but obviously I don't. Any help would be greatly appreciated.

Thanks,

[Freesail99]

The current issue of Cruising World has an article on how to bleed a diesel engine.

[Rickm505]

When you say you changed your fuel filter, is the it the primary 'Racor' type you changed out, or the Yanmar secondary fuel filter?

I'll assume primary. On my boat my fuel lines run 10 feet from primary filter to lift pump. Changing the primary puts a serious air gap in the fuel line by the time I get it full of fuel. The engines start, then litterally run out of fuel. I have to pull the fuel line off at the lift pump and use my mouth to suck the full through the line. Then use the lift pump to fill the fuel bowl of secondary filter and then I crack the banjo at the injector open a bit and use the lift pump until I have fuel at that point.

Engines start fine.

Rick in Florida

[Rickm505]

I just noticed you have a 2GM. If you really feel the engine had been bled correctly, I'd move on to the #2 cause of older, raw water cooled engines, quitting.

Pull the mixing elbow off, it's probably clogged and this will cause the symptoms you describe.

Rick in Florida

[camaraderie]

John...here are the steps...
BLEEDING THE FUEL SYSTEM
(Purging of air which causes shutdown)
This bulletin contains helpful information for bleeding the fuel system of a Yanmar Diesel and other
small diesels as well. Please post where your field service personnel can review.
Since the presence of air in the fuel system anywhere between the fuel tank and the injector will
"use a no start or erratic running condition, always bleed the air from the system when the fuel
system is disassembled, filter changed or run out of fuel.
1. Make sure fuel tank off is in "on" position.
2. Bleed the air from fuel filter. Loosen the air bleed screw at the top of the fuel filter body and
operate the manual handle the lift pump until the air bubbles completely expel in the fuel flowing
from the filter.
3. Bleed the air from the fuel return pipe. Loosen the connector bolt of the fuel return pipe installed
on the fuel injector, and bleed the air by operating the manual handle of the lift pump. (If there is
more than one injector, bleed the one at the end of the line).
4. Bleeding the air from the fuel line - (line from the filter to the injector pump). Loosen the air
venting screw at the injection pump and operate the manual handle of the lift pump until an the
air bubbles are out.
5. Bleed the air from the fuel injector. Loosen the nipple on the fuel injector side, set the throttle to
half and the decompression lever to the decompression position and crank engine. When no
more bubbles appear in the fuel flowing from the end of the injection pipe, re-tighten the nipple.
THIS BULLETIN IS FOR INFORMATION ONLY AND NOT AN AUTHORIZATION FOR REPAIRS
*****************
Hope that helps a bit but ALSO check if your hand operated lift pump is actually pumping fuel. There are a lot of problems with these Lift pumps and gaskets. Easiest way to check is to loosen/remove first fitting after the pump (not the exit fitting of the pump) and check for good flow as you pump. If you get little flow or constant bubbles with the flow...you have a leaky gasket and the ENTIRE pump needs to be replaced (about $75) and here's a couple of places to get one from quickly:

Distributor Union (New Jersey)	Mack Boring & Parts Co.	2365 Route 22 West 7083 Union (New Jersey)	908.964.0700 908.964.5032 Mack Boring & Parts Company - The Power Behind The Power
Dealer Myrtle Beach	Hague Marina Inc.	Myrtle Beach Yacht Basin 29577 Myrtle Beach	843.293.2141

If you DON'T have a leak at the pump...
then it is simply a matter of following the piping around and bleeding each fitting until you see no bubbles. Check your hi-pressure fuel pump in the manual as some have TWO bleed screws.

I don't know YOUR engine John so some others may be able to be more specific. Your symptom SOUNDS like a clogged line OR a line getting air into it assuming you don't have any other symptoms like overheating or water in the oil. Rick's suggestion should be checked too!
Good luck on the fix & hope the above is helpful.

[PBzeer]

Mine is setup with the primary, after the lift pump, then to secondary. Not going to try anything in the dark, was hard enough in the light. If all else fails, I'll get some use out of my TowBoatUS membership and have them tow me into Southport in the morning. Meanwhile, I'll just wander around all night.

And no, I'm not sure I bled it correctly. Thanks for the help. At least I have sails

[Rickm505]

I'm certain you'll have this fixed pretty quick. Just a quick question, when was the last time you fueled the boat? Does your setup have a water separator? If it does, it's worth checking the bowl and see what you have in there.

The 2GM exhaust mixing elbow should be easy to access on a 2GM as it's the highest point of the engine installation as I recall. I have twin Yanmar 1GM10s in my cat and the mixing elbows come off in about 5 minutes. If it's clogged, you can probably open it up by pulling some of the carbon out of it. This should be enough to get you into your slip. If the problem is fuel line bleeding, well, it's just logical, follow the fuel flow until you know you have fuel at the input to injector pump.

If fuel is at the input to the injector pump and she still won't start, I'd humbly suggest that you grab that tow.

Rick in Florida

[keelime]

I have a yanmar 3gmd and encountered a similar plroblem after changing my fuel filters. My engine seems to get little air bubles stuck in the high pressure fuel lines.
When using your manual fuel pump to bleed the injecters, make sure you are at full throttle, those little manual pumps need all the help they can get in order to pump enough fuel to get out all the air.
Also, depending on how long ago you changed your filters, you may have nocked loose some gunk into your injectors. Good luck

[keelime]

Sorry, I forgot to mention to do this when cranking your throttle to bleed your injectors.

[sailingdog]

BTW, if you're cranking the engine for more than 20 seconds or so, don't forget to shut the raw water intake for the exhaust system off—if you have a water lift muffler, so that you don't get water in the engine through the exhaust valves and hydro-lock the engine. Hydro-locking the engine will just ruin your day. And don't forget to open the intake when you get the engine started.