# Bleeding a Yanmar 3GM30F



## jlmarra (Oct 30, 2001)

Hello All,

We have a Yanmar 3GM30F in our 1990 Caliber 33. After a pleasant early evening sail. We fired up the engine to motor into the inlet of our harbor and had problems with engine stalling at RPM's over 2000 and under 1000. Once I found the range she would stay running I was able to limp her into the harbor and to our mooring.

The gauge next to the Racor filter was clearly in the red. I usually have the yard spring commission the engine and the filter usually lasts through our 6 month Long Island sailing season. I've actually never had to change one myself.

I read through various diesel engine books that I have aboard including notes from a Mack Boring seminar I attended a few years back.

I removed the Racor filter and looked inside it didn't look dirty, but like I said I never changed one before. I filled the new filter and bowl with fuel right to the top. Smeared some fuel on the O-rings and hand tightened her up as the books recommended.

Then I proceeded to remove the bleed screw (phillips head) from the secondary filter. I can't believe Yanmar chose to stick the thing up under the heat exchanger . I was able to get a wrench on it but had no room to swing the wrench. I had to remove the other screw on top of the filter to remove the bleed screw.

I operated the lift pump and was not getting any fuel out of the top of the secondary filter. I put back the outer screw and tried again, nothing. Actually I wound up with a small amount of fuel on my fingers which I was using to operate the lift pump. For those of you not familiar with a Caliber 33, starboard side excess to the engine is visually limited. I use a mechanics mirror just to put the oil dipstick back into the engine. I had to use a mirror to see the screws on the top of the secondary filter.

I replaced the bleed screw on the secondary filter and started the engine. She ran for about 2 minutes at about 1000 RPM's before she stalled. I was not able to get her to start after that. Finally I said uncle and called the mechanic where we moor our boat.

The mechanic was not able to get fuel into the secondary filter. He found that the hose running from the primary filter to the fuel pump was cracked, probably original hose. He replaced that, but still no fuel. He ordered a new pump which he is waiting for.

I didn't really delve into it any deeper because I figured I was doing something wrong. This is from someone that when my SUV doesn't run correctly I take it to my mechanic.

Depending which book you read. Some say that in most cases you only need to bleed up to the secondary filter while other books say you should bleed the whole system up to the injectors .

I just haven't been able to figureout the iron Jenny . Give me circuits, electronics, computers, and I'll make them work . Gears, belts, and fuel lines have got my number .

Thanks for your replies.

Regards,

John
S/V Sailor Dance
1990 Caliber 33
Long Island Sound


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## sander06 (Sep 18, 2003)

We had the same engine and same problem. The deal with the Yanmar's is that when the fuel pump goes, your're dead in the water. We had some little outboard squeeze bulbs in the fuel line for priming and I finally bought an electric fuel pump installed in-line after the racor filter to supplement the yanmar pump (which is a piece of crap). After installing the new fuel pump, no problems.

Good luck! Nothing worse than a diesel that won't run.

Steve


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## billangiep (Dec 10, 2003)

From Yanmar.... BLEEDING AIR I also use a priming bulb installed in line before the filter to assist in bleeding filters.


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## SteveInMD (May 11, 2007)

The fuel system has two sections - a low pressure section and a high pressure section. It's important to understand where one ends and the other starts. I'll try to describe that here. Once you understand them you can then learn how to bleed them. 

It's helpful to know where the lift pump is and where the high pressure injection pump is. From the bleed point entering the high pressure pump back towards the secondary fuel filter, lift pump, primary fuel filter, and tank is all part of the low pressure fuel system. Removing air from this system is always step 1. If you work on the low pressure system, for example changing fuel filters or the lift pump you do not normally need to bleed the high pressure system. The high pressure system includes the high pressure fuel pump, the high pressure fuel lines, and the injectors. To find the high pressure pump, follow the lines coming off the injectors to where they meet in a row on top the the high pressure pump. Another clew is the final bleed point from the low pressure side, it too attaches to the high pressure pump.

If you work on the high pressure system, such as replace a high pressure fuel line, or as in your case, run the engine without the low pressure system being air free, you introduce air into the high pressure system.

(Note: You can also introduce air into the high pressure system by completely filling the secondary fuel filter with fuel before installing it on the motor. Leave it empty or no more than half full before installation. People do this to minimize the hand pumping, but it traps a slug of air in the low pressure system, which will end up in the high pressure system)

Once you get air in the high pressure system you need to bleed the low pressure system first, then bleed the high pressure system.

It sounds like you are familiar with bleeding the low pressure side. The high pressure side is pretty easy... once the low side is air free, follow the lines fro m the high pressure pump to the injectors. This step shows you which is the injector inlet and which is the outlet (or fuel return). Open the connection at each injector 1 full turn. All injectors are bleed at the same time. (The engine cannot start with these lines open). Do not remove the line from the injector or bend it. Now just turn the engine over with the starter until fuel comes out of each loosened nut. Only a very small amount of fuel is pumped each revolution. (Do not pull out the engine stop during the process or it wont work.) Then tighten each fuel connection at the injectors. The need to be tightened more firmly than the low pressure side since they run about 2,500 psi. Now try to start the engine. If it starts and runs for 10 minutes you are done. If it stalls, re-bleed the low side, then the high side again.


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## HerbDB (Sep 30, 2000)

You did not say if you checked the engine fuel filter. If you are following Yanmar's recommendation to run a 10 or 30 micron (depending on who you ask) in the Racor and a 2 micron on the engine, you could easily have a clean looking Racor and a fouled engine filter.

I have had the same engine in my last two boats. My experience with the symptoms you mentioned is that it is usually caused by a fouled fuel filter or less likely air in the line due to a loose or split fuel line before the pump. I personally use a 2 micron element in the Racor and rarely ever have to mess with the engine filter which is harder to change. There was a discussion about this recently on another thread. Try searching for "racor".


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## sailnsoul (Jul 12, 2015)

Hi---
Can you provide more info about your installation of an electric pump, please?
Thank you,
Doug


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## smurphny (Feb 20, 2009)

On the 3GM30F, there is a *second bleeder screw for the injector pump*. It is not obvious, being under the exchanger hose on the top/left side. I have a 3GM30F and took a while to find that bleeder. If you don't first bleed the filter and then the injector bleeder, the engine will never start. Once you get fuel to the injector, the engine will fire right up. Don't mess with your injectors/banjo fittings YET. Once you crack those banjos, you may wind up having to replace the washers. Your original problem was almost certainly the cracked hose. You just need to bleed the second bleeder screw. +1 on having an outboard squeegee.


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## DaveB (May 21, 2017)

I have a 2001 Beneteau 361 with a 3GM30F Yanmar Engine. I changed my Racor primary filter several times as follows:
1. Place a pan under the Racor filter, then unscrew the filter element and water seperator section as one unit.
2. Empty the fuel from the old filter element and water seperator into the pan. 
3. Remove the old filter element from the clear water seperator section. 
4. Clean out any particles in the clear water seperator section.
5. Install the new Racor filter element onto the water seperator section with an O-ring between them and place the square ring gasket on the top of the filter element.
6. Pour fresh fuel from a fuel jury can (or from a small container with fuel in it).
7. Once the filter element and seperator section are full of fuel right to the top, keep it level and thread the assembly onto the fixed top of the Racor filter housing.
8. No bleeding is required. Just start the engine and it will run with no problems.
Note: I have never changed the secondary fuel filter element on the engine because it is too difficult to reach.


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## albrazzi (Oct 15, 2014)

DaveB said:


> I have a 2001 Beneteau 361 with a 3GM30F Yanmar Engine. I changed my Racor primary filter several times as follows:
> 1. Place a pan under the Racor filter, then unscrew the filter element and water seperator section as one unit.
> 2. Empty the fuel from the old filter element and water seperator into the pan.
> 3. Remove the old filter element from the clear water seperator section.
> ...


16 years on a filter that's pretty good, I would get one in there. I think you're pushing your luck.


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## DaveB (May 21, 2017)

I took your advise and changed the secondary fuel filter on my 3GM30F on my Beneteau 361. It was not easy but this is how I did it.
1. I placed a small plastic container under the filter housing to catch the fuel in the filter
2. Using a flathead screwdriver and towel to prevent marking the filter housing lock-ring raised bumps, I tapped the end on the screwdriver against a raised bump to loosen the lock-ring on the filter housing. 
3. To make it easier to manually turn the lock-ring, I removed the two bolts that hold the filter housing to the engine and the one bolt that holds the discharge tubing close to the engine.
4. I then could turn the lock ring manually and remove the bottom section of the filter housing and remove the filter element.
5. I then installed the new filter element (placing the filter element onto the top of the filter housing with the hole on the element up) then reinstalled the lower section of the filter housing and the lock-ring.
6. After manually working the fuel supply pump up and down about 100 time as instructed in the engine manual with the vent valve opened on the filter housing, nothing was coming out the vent valves.
7. The filter lock-ring was then removed and the filter housing bowl was inspected to see how much fuel was pumped into it. It was still empty. Evidently the manual pump activation was not working.
8. The filler bowl was removed and manually filled to the top with fuel from a jug. 
9. After carefully reinstalling the full filler bowl and lock ring, I turned the turned the egnition key for the engine for about 3 seconds.
10. There was some fuel the came out the filter vent.
11. The vent screw was then closed and the filter housing assembly was then reattached to the engine with the two bolts and the discharge hose hold down bolt was also reattached. 
12. Turning the engition key started the engine with no problems.


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## ajoliver (Feb 23, 2007)

Note to self - 

Stick with Nissan outboard


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## chip (Oct 23, 2008)

My process usually goes:


Change the fuel filters
Bleed the water separator
Bleed the Racor
Bleed the fuel pump
Bleed the on-engine fuel filter
Bleed the injectors
Start the engine...it will start perfectly 
Run the engine for a good 10 minutes at the dock to make sure everything is kosher (it will run flawlessly)
Make it 15 minutes...she needs to be not only merely bled, but really most sincerely bled
Get 2/3 of the way out of your slip with a strong cross wind and have the engine start choking and dying because THERE IS APPARENTLY NEVER ENOUGH BLEEDING
Coax it through the marina with alternating blasts of power and revving in neutral to keep it running
Stall it as you get to the skinniest part of the channel while navigating by video game since there are no damn buoys in yet
Defiantly get her up to cruising RPM and run the rest of the way out of the creek, which will cause everything to self-resolve


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