Last week I replaced the oil and fuel filters, impeller, and changed the oil on my Yanmar 2GMF after it being two years on the hard. I also poured in some fuel additive to the half full tank. I hooked up a bucket with water and reconnected the raw water hose to the bucket. It started and ran for about a minute and stopped. I tried restarting but the batteries died. This weekend I replaced the batteries and decided to replace the belts, too. To do so, I had to unbolt the alternator which dangled for a few seconds on its cables. I reconnected everything and tried starting it. No luck this time. Tried a couple more times and stopped. When I went to look closer at the engine, I found a loose wire with a connector on it that I couldn't find a home for (see pic). I realize that at times there are superfluous cables depending on the engine type (as the engines may share cable bundles). And the mystery connector may be a complete red herring to why the engine doesn't start. At any rate--these are my clues. Any suggestions? Thanks
Yanmar 2GMF-- Won't start + mystery connector
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First off, the problems with a diesel starting are usually fuel related. I'd suspect air in the fuel system due to the fuel filter change.
Carefully bleed the fuel system again.
Ken
Carefully bleed the fuel system again.
Ken
I'm with Ken..especially since you didn't mention that you bled the engine after the fuel filter change.
Nope, didn't bleed the fuel. Looks like I get to learn something new....First diesel after years with an Atomic 4. Sigh...
When I had a 2GM20F, I only had to bleed at the top of the secondary (Yanmar) fuel filter, so it's not all that bad. It's good to replace the little plastic washer under the bleed screw beforehand. If you don't, you'll find yourself cranking too hard on the bleed screw to seal it, which can then strip out the threads on the aluminum filter housing. (The PO on that boat left me that mystery to solve!)
If it helps you get oriented, the attached pdf contains bleeding instructions from the official Yanmar Service Manual for the GM series engines.
Excellent! That doc plus a few YouTubes and I’m set to go. Thanks
Update: Couldn't find any useful YouTubes showing how to do it. One goes on for 15 minutes and consists of a guy guessing what to do! Another one recommends installing an inline primer pump but commenters say these rubber primers eventually go bad and end up leaking fuel
Update: Couldn't find any useful YouTubes showing how to do it. One goes on for 15 minutes and consists of a guy guessing what to do! Another one recommends installing an inline primer pump but commenters say these rubber primers eventually go bad and end up leaking fuel
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I changed both the fuel filters on my Yanmar 2GM20F a few weeks ago. What I did was to fill the filter cups with fresh diesel and then screw them on. I was able to start it without bleeding the air out. Filling them minimizes the air that was in the system. When I started it, I ran it out of fairly high rpm, probably about 1500 rpm. It stopped a couple times but always restarted.
Mike
Mike
I have that same unused wire on my 2GM. let me know if you find out what it is for? LOL
The outboard Primer bulb has helped me greatly with filter changes. It has only been in about a year now, so I don't know how long they last. They are cheap enough to change out every time you change fuel filters if you are worried. I will probably check mine at filter changes, and change when it think it needs it (I would suggest you keep a spare on board in case of Murphy)
The outboard Primer bulb has helped me greatly with filter changes. It has only been in about a year now, so I don't know how long they last. They are cheap enough to change out every time you change fuel filters if you are worried. I will probably check mine at filter changes, and change when it think it needs it (I would suggest you keep a spare on board in case of Murphy)
Would installing a primer now eliminate the need for bleeding the system now or is it something that should have been done before changing the fuel filter? Would you happen to know the fuel line diameter? The bulbs are sold for 3/8" and 5/16". (I may bleed the system anyway just to practice the technique)
The hand priming pump built into the engine is way too small for its purpose. It functions, but can take over an hour of hand pumping to re-prime. The primer bulb helps you bleed the system a lot quicker. It allows you to push fuel through the lines and new filters until it comes out the bleed valve that you open at the top of the secondary filter.
Last time I had to do this, it only took 2 to 3 minutes to get the engine back running. You place the squeeze bulb between the fuel tank and your primary filter.
I didn't know what size my fuel line was as well, so I bought both sizes of squeeze bulb, and returned the one I didn't use for a spare of the correct one.
Do you remember which one you returned? 
BTW--I think the arrow in your pic is pointing to the wrong screw. Other diagrams and pictures I've seen indicate that the bleeder screw is the one closer to the engine block.
BTW--I think the arrow in your pic is pointing to the wrong screw. Other diagrams and pictures I've seen indicate that the bleeder screw is the one closer to the engine block.
Sorry, I don't remember which size. That is the screw I bleed with the other one is a bolt.Do you remember which one you returned?
BTW--I think the arrow in your pic is pointing to the wrong screw. Other diagrams and pictures I've seen indicate that the bleeder screw is the one closer to the engine block.
OK, thanks. I was going by this drawing from the Yanmar manual....
I was joking about the returned bulb... ;-)
Attachments
Once an engine quits due to fuel starvation you may need to bleed the system to the injectors. Pump the fuel and bleed it to the filter. Loosen the screw on the banjo fitting going into the fuel pressure pump or the banjo fitting itself and bleed the fuel to this fitting with the primer pump. Loosen the nuts on the injector tubes at the injectors and roll the engine over. Turn off the water intake. Keep rolling the engine until there is a good amount of fuel coming out of the injector fittings. Tighten the nuts on the injector tube and the engine should be ready to start. It's a good idea to clean up the spilled fuel.
You have to bleed the fuel all the way through the system to purge the air.
Good luck.
You have to bleed the fuel all the way through the system to purge the air.
Good luck.
I have a primer bulb. Works great!. Another option is a Racor 500FG2 filter with integral primer pump. About $195. As others have said, the manual fuel pump on the engine is insufficient to get fuel out of most tanks. Most likely you ran the engine dry and it is almost impossible to start the engine without some kind of primer bulb to pressurize the system. I went through the same issue with my 2gmf.
I've done some more research and have come across some arguments being made for installing an in-line electric priming pump. I have several questions: Is it more effective than the rubber bulb? When not operating (I assume I would install a switched circuit to it to turn it on when priming for bleeding the fuel), does it obstruct the fuel flow? Finally, should it go between the tank and the first filter or between the first filter and the engine? Thx
The only time that you need the priming pump would be when you have air in the lines, or essentially when you change the filter or if you should happen to run out of fuel. I don't see any reason for putting in an electric pump, just a priming bulb should be sufficient.
There is a lever on the side of the engine to allow you to prime the fuel, but I have never been able to get that to work, at least not on my engine.
Mike
There is a lever on the side of the engine to allow you to prime the fuel, but I have never been able to get that to work, at least not on my engine.
Mike