Air in Fuel Line

[Alan Eland]

Gordon,My '89 Hunter 30 has a Yanmar 2GM20(F). I changed the fuel filter element yesterday and made the mistake of not filling the filter "cup" with diesal before reinstalling and starting the engine(the cup has since been filled). I did bleed the air from the bolt on top of the filter. But, as you can probably guess, the engine started briefly and then stopped. Attempts to restart have only served to drain the batteries! After talking with some guys at the marina it appear that I have air between the filter and injection pump. Is there an easy way to bleed these lines? Do I only have to worry about bleeding the line between the filter and injection pump or could air have gone beyond this line and into the pump? Timing is everything. I have a trip scheduled to Block Island tomorrow morning. I'll be trying to bleed the line tonight after work.Thanks in advance.Alan

 

[Frank Pratt]

another bleed screw

Follow the fuel line from the small Yanmar filter down to where it enters the injector pump, there is a 10mm blead screw that is tapped into the bolt that connects the line to the injector pump. it has a phillips head on it but I find it easier to manipulate with a box end wrench

 

[Steve Dion]

Franks correct.

Alan:If you fixed it before you get this great. Otherwise what you need to do is re-bleed your system. Now that you have fuel in the lines it should be easy. You first need to do the lower 10mm with the phillips head until fuel comes out and then tighten it down. Then move up to the one on the secondary filter that you already did. Same procedure keep pumping until fuel appears.Do not do anything beyond this point, you will be getting into the high pressure side of then system. They engine should start and keep running like a clock.PS: Just a tip. Use some bright nail polish or paint to mark these bleed points. It makes it easier to find them in an emergency. Good luck and happy sailing.

 

[Gordon Torresen]

Not running yet?

The two previous posts gave good info for bleeding the low pressure side of the fuel system. It is important to have a clear fuel flow at the bleeder on the injector pump. All this bleeding, so far, should have been done by operating the lever on the side of the lift pump. Now you have to bleed the high pressure side. this is done by cranking the engine. Before you hit the start button, turn off the sea water pickup valve. Now, with a 17mm open end wrench,loosen the hex nut on the HP lines where they attach to the bottom of the injectors - only needs to be loosened about one flat of the hex. Nest, open the compression release valves, move the throttle to full open (make sure the stop cable is all the way in) and crank the engine until clear fuel drips out of the injector tube. Stop cranking, close the compression releases, pull the throttle back to idle and start the engine. If it starts, open the sea water cock promptly and go sailing. This usually works. If you have been trying to start the engine for a long time, you may have dried out the HP pump. If you don't see fuel at the injector lines when bleeding the high side, get back on line and I will take you through a slightly more complicated step that is usually not necessary.