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Discussion Starter #1
When I replaced my primary fuel filter, I pumped then priming pump lever for a few minutes but no fuel ever came up through the bleeding screw. I assumed that maybe the little lever did not do anything, tighten the bleeding screw. As suspected, the engine started and soon died because of air in the fuel line. I then cracked the injectors and ran the starter while pulling the stop button. Again, no fuel came out of injectors. So, I tighten the injectors back up and tried to start the engine at full throttle. Somehow it did start and ran very roughly before dying again. I repeated the process a few times and finally, it ran fine. I can only assume that there is some kind of self-bleeding with the 3GMF but I'd like to know why no fuel came out of the bleeding screw..
 

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Did you fill the filter bowl with fuel before installing it? If not, you had a LOT of air in the system. The priming lever on the 3GM lift pump only pumps a tiny amount with each stroke so would take a long time to clear that amount of air. I filled the Racor on my 3GM30F with fuel after changing the filter and still had to bleed the system to get it to run. I suspect if you open the bleed screw and pump the priming lever you will get fuel now.
 

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Another thing to keep in mind is that if the pump cam is in the wrong position--luck of the draw--you can move that little sucker all day and not pump any fuel. You should be able to feel a little "pumplike" resistance over some of the movement. If not, rotate the pulley a little bit and try again.

If you really changed the primary--which would be the Racor or whatever is outside the engine--and didn't fill it, you could easily have 10 minutes of pumping to do, maybe more. If you just replaced the secondary filter--the one that is on the front of the engine--a few minutes should bring some fuel out the bleeder. BTW, it's easier to see if you are pumping something if you leave the bleed screw almost closed--you'll be able to see some air and bubbles there, especially if you put a drop of diesel on the bleeder screw as an indicator.
 

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I had fuel line issues with my 3GMF several seasons ago (there's posts in here somewhere) and once spent a good half hour pushing the lift pump with no success, only to find that I had been moving the lever within the clearance range (which was about 1/2") and stopping at what I thought was the end of the range but was actually the resistance point where the pump range begins (less than 1/4"). While I felt like a dope for those many frustrating minutes of non-pumping, it only took a few seconds for fuel to flow from the bleed screw once I was activating the lever properly - and then I felt much smarter.
 

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Discussion Starter #5
Thanks for all the pointers. I think I had the lift pump lever in the right position because I could move it about 1" up and down. Maybe I did not pump long enough.. I like the idea of putting a drop of diesel on the bleeding screw and see if any bubbles are coming out. I'll try that next time.
 

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There is an inconspicuous air bleeder in the injector pump. It's partially hidden by the water line. I pulled my hair out before realizing this a few years ago. Also, the fuel pump lever takes a LONG time to get any fuel into the bowl.
 

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I dealt with this last month. There are several spots to bleed and an order to it I found. Make sure all air is OUT of the new filter - use bleeder on top of filter. Then on Yanmar - bleed from screw where fuel enters (top front of engine- I think this is injector pump being references above) hard to reach so you need an off set wrench. Make sure you bleed that well BEFORE you try the pump. After that is bleed THEN try bleeding from the handpump - may take a while so keep at it, the hand pump was the LAST to bleed out in this process. But once that was done successfully I had no more air in the line issues (this had plagued me for 2 days) because I was doing what you are doing now.

You have to get the fuel flowing with the hand pump in order for a full bleed to take.

I would not mess with the injectors...

Sean
 

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I think you already have air between the filter and the injectors. Pumping that little lever will do little now as you cant pump it through the highpressure injector pump. I would crack the fuel lines at the injectors again and crank the engine. you did the right thing but did not do it long enough.
 

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I just installed a new racor with a priming pump right on it. You can bleed the whole engine right from there! No more pumping that little lever on the lift pump 50 million times!
 

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Over Hill Sailing Club
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The issue is not really as much pumping fuel in as getting the air out. The injector pump is a stopping point for any effort to pump. There is a bleeder, as I mentioned above, under the front of the hose coming out of the heat exchanger. Look at the attached link Google Image Result for http://coxengineering.sharepoint.com/siteimages/IMG_2648.JPGto the picture of a 3GMF. Find the hose clamp on the front of the exchanger. Directly below and under it is another bleeder. No amount of pumping will force the air past there unless it is bled off so fuel can get to the injector pump. Once you get fuel there, it goes pretty quickly to the injectors. The banjo fitting on top of the farthest banjo can also be cracked a bit to speed this up but be prepared w/ a new copper washer in case of leak.
 

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2Gm20 yanmar primary filter change
Dirty job be prepared. Make sure you can catch the fuel that falls out.
If you can pre fill the filter and bowel before attaching gets rid of most of that troublesome air.
Forget the bleeding screw at the top take the hose off the fuel out let at the top of the filter.
When you get a free run of fuel put the hose back on . If fuel dose not run out then open the bleeder at the top of the filter
This works I don't know why.
Now go to the priming pump and take the fuel hose off the inlet wait to you get free flow of fuel . (Gravity fed) When you do put that fuel hose back on. Now loosen the out let side of the hand pump you should get fuel if not pump the sucker make sure you use a full stroke or you will be there until dooms day.
By pass the secondary filter and now loosen the inlet to the high pressure pump and give that little sucker some more pumping with luck you will have fuel coming out. I loosen the inlet pipes to the injectors as well at the start to make sure there is no resistance and after all if fuel is coming out there your in business.

Tighten everything up wipe away all excess fuel cross your fingers and start her up.
 
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