Yanmar fuel supply problem

[Wahoo Sails]

Pat,
Plenty of fuel in both tanks .... just none at the engine when this occurs. I have to agree, it's the duration between occurances that vexses me .... most people are pointing fingers at the mechanical pump .... but at 400 hours? I guess it's possible, but not likely ... and would it run 40 hours on a bad fuel pump?
I think my next step is to replace all of the fuel line & check all of the fittings. If that doesn't get it ... then something that hasn't turned up on this thread ... will pull the pick up tubes out of the tanks & check for problems there. I sell pick up tubes almost daily ... so i know that this could be the problem.
Bob

[Boracay]

If all the fittings on your tank are airtight could you have a blocked breather?

[Rick]

Do you have a fuel return line that is not properly returned to the tank without mixing with the drawing line at any point?

[never monday]

Chris triggered someting in my mind.
Does this occure 40-50 hrs after refueling?
Check the 5/8" vent hoses from the tanks. Spiders like to build nests in the thru hull fitting for the vent. This blocks air return into the tank and creates a vacuum in the tank.

[Alan Wheeler]

Do you have a fuel return line that is not properly returned to the tank without mixing with the drawing line at any point?

Rick, that shouldn't be a problem. It's actually my prefered way of plumbing fuel systems and the technique has been done this way for a lot longer than I have ben around with no issues I have ever seen or heard of.

[S/V Elusive]

Ahhh .. the joys of playing with the fuel system. As one of the above gents mentioned - a little piece of something can lodge in a line (REAL easily). It will restrict flow, but not enough to cause the engine to be starved - AT LOW RPM. Once you kick up the rpm for a while, it wants to draw more ... and it can't. See if that fits your pattern of use, with the last time you used it, running it above your norm for a bit ... and, as someone mentioned before, don't ask me how I know ... oye.

[S/V Elusive]

And another thing ... Racor filters ... I sure hope that everyone knows that they changed the filter elements - to fit the NEW design. But, whoops, it turns the older style racors into basicly a bypass situation - does NOT FILTER. They also (until recently) were not including an adapter with the filter elements. You had to KNOW to order them. NO one around here knew about it ... I'm still fighting with crap in the system. There ARE alternatives to Racors! I can't tell you how "happy" I am with them and their customer service/marketing idiots that neglected to fix the problem and get the word out in a timely manner. Guess they thought it wouldn't matter.

[never monday]

Elusive,
I don't think the blame lies with Racor. I've known about this for over a year and had parts. As soon as Racor was aware of the problem they made adapters available at no charge. If a customer was unwilling to wait for the adapter they gave instructions on how to make one in less than 5 min.
There are other options to Racor, but none are as good as Racor.

[hellosailor]

Bob, are any of your fuel line fittings assembled with crush washers? Crush washers are supposed to be used once and then replaced, and if someone bleeds a fuel line they usually don't bother to change the crush washer--which can cause an air leak to drive you nuts afterwards.

Don't ask me why I have religion about changing crush washers.<G>

[S/V Elusive]

Pat ... could very well be ... but NONE of the retailers/disti's around my area knew ... *I* found out on this forum ... perhaps from you ... And, they may very well have made them availlable ... if you asked ... if you KNEW to ask. They eventually got around to including the adaptors in with the filter elements (at least they did on the last one I bought).

[Wahoo Sails]

As I mentioned earlier, the first time I changed the filter, there was a fair amount of gunk on it (although not grossly so) and nothing in the filter bowl at the motor, so it would appear that the filter is doing it's job properly. The return line on the 2GM goes from the injector pump back to the final filter housing ... not the tank ... factory arrangement, this is my 2nd 2GM and they were both alike in that respect.
It is certainly possible that the breather hose is comprimised in some way ... suppose I could pull it off the tank and blow through it ... see what happens.
I found out on the 1st 2GM that Yanmar uses plastic washers at the bleed screws ... uh ... seem's a little wierd to me, but seems to work OK.
Just dawned on me that the original filter I changed may have predated this Racor change ... is there a way to tell visually if it has been corrected?
Bob

[Rick]

If you can run the fuel return line back to the tank or even a "day tank" that you can drain into either fuel tank when convenient then when you change filters you run the electric fuel pump and force all the air out of the system that you cannot guarrantee that you do with your existing setup.

I used to have this problem until I did exactly that with my last boat and made sure that my present one does as well.

[S/V Elusive]

As to the Racor filter - the old style filter cartridge had end discs/plates that were solid and on the same plane (they were both round ... top and bottom, and flat). The NEW style has a cylindrical cavity in the middle - about two inches or so diameter, and about an inch and a half depth. There is an adaptor that 'plugs' that cavity - fits in the cavity. This is for the 500 FG (and perhaps others?) model. If your Racor uses a 2010 element, you need to check.

[never monday]

The return on all GM series run from the rear most injector to some where. Usually this is plumbed to the tank. Almost never is it run back to the injector pump.
You can visually inspect the Racor to see if it's bypassing. Turn off the fuel flow. Open the top and push the element down as far as it will go. If you can see a part of a hole on the center stem then it is bypassing. The fix is to get a spacer from Racor or cut a piece of hose to push the filter up. This is only applicable if you have filter elements that are tan with colored writing. If you have the old style colored end filters it isn't applicable.

[S/V Elusive]

Just to clarify what Pat said (sorry Pat ... I was confused and had to read it twice - you are absolutely correct - but ... ) The OLD style of filter elements were a solid color - ie: tan, brown etc. The NEW style of filter element (and if you have these, it COULD be a potential problem) are all the same color with COLORED WRITING. The color of the old style filters elements indicated filter pourousness (sp? ) such as 2 micron, 5 micron, or 10 micron. Okay ... are we ALL confused now??