Self bleeding system

[Steve Hansen]

What a wonderful resource this site has been. I enjoy browsing and reading the various topics. Something I've come across and not quite clear on is the idea of a self bleeding system. From what I've gleaned, the bleed valve should be opened a half turn to allow a fuller fuel flow through the system thereby "polishing" the fuel through the 2 micron filter. I know there is a bleed valve on the Racor, and one on the engine mounted filter. I'm assuming neither one of these are the ones to open. And am thinking there is a third valve somewhere on the line. Engine is a M25XP. Any thoughts? Thanks. Steve

[Jeff Kaplan]

steve, the bleed screw is on the engine,  top, on left side toward front, if you are looking aft from inside the boat.  its a thumb screw and looks like a small wheel. thats the one to open to bleed the system. i have the m25, but it should be in the same spot on the xp. i had always left it closed, but i read a post by ron, that on the older engines, the screw should be left open a bit, preventing air from being trapped, thus becoming a self bleeding system . as i am about to start this season, i have left the screw open about a 1/2 turn....jeff

[Steve Hansen]

Thanks Jeff,
I thought that thumbscrew may have been for that, wasn't sure and needed the confirmation. Steve

[Terry Forshier]

My boat befor the Catalina 34 was an O'Day 30 with a 2QM15 Yanmar. To bleed it the previous owner had installed a squeeze bulb (like in a outboardf motor line) I would turn the top nut until it barely cracked open then I would squeeze that ball and when the fuel squirted out the air was out.
It was great when I changed fuel filteres, pruged the RACOR or somehow got a bubble in the line. In the past 15 years I used it several times. I was told by a surveyor it was not safe but it sure helped when I needed it.
Terry