Minor Fuel Leak Yanmar 2GM20F Engine

[pfaffk]

Years ago I had to replace the Fuel filter on my Yanmar 2GM20F Engine because when I went to bleed the fuel line the fuel filter threads came out along with the screw. I replaced the fuel filter, replaced all the fuel lines and all was well, or so I thought. After some time I noticed a fuel leek on the input hose to the fuel filter, I tighten the hose clamp, but the leak was still there. I then replace the flexible fuel hose, but it still leaked. I put on two hose clamps, and it still leaked. During this long period of time I kept those oil absorbing pads under the filter.

So once again this year I once again decided to investigate the problem. While working on it I noticed that the hose went onto the barb very easily, I had a AH HA moment, I will replace the 5/16 in hose with 1/4 in hose. That did not work as the hose would not fit. Then notice that on the hose barb there ring indentation around the barb as if it was missing an o-ring. I bought some o-rings at the hardware store but they would not stay in place when the hose was pushed on.

I am now looking to the great hive mind of experts here to see if you have a solution to my problem. Attached are 2 pictures, the first is of the fuel filter / barb with the hose pulled off, the second is from he Yanmar manual. The manual says that there should be a rigid pipe between the fuel feed pump and the Fuel Filter and I cannot find the the type of hose barb that I have on the engine. What I have came this way from Hunter as I bought the boat new.

I want to thank everyone for you help in advance.
Ken Pfaff
S/V Wanderlust

 

[Charles Erwin]

No O ring there. One places the rubber hose then applies the hose clamp above the bulge (now covered by the hose.) Once clamped the hose can't slip off past the bulge.

As to the leak do this: Remove the banjo fitting (the inlet) and replace the copper seals (called crush washers) with brand new never used before crush washers.

The stock set up (shown in your diagram) is formed steel tube from the pump to the filter inlet. That is commonly done for all lines on the pressure side of any fuel pump. These get replaced with flexible line because the steel ones are expensive. Rubber fuel line is just fine. And considering the maximum pressure is no more than 5 lbs/in there is no way that clamped rubber joint is going to leak. You can use two clamps at each fitting (total 4 clamps) if you have doubts.

Charles

ps Save the fuel filter canister. The threads are very easy to restore with a heli-coil insert. Any machine shop or competent auto repair can do this for much less than new canister. The bonus is the heli-coil threads are stainless and will last forever.

 

[pfaffk]

Charlie, Thanks for your quick reply. But there is no bulge on the hose barb and the hose goes on very very easily, in my opinion way too easily and that is why it leaks. The banjo fitting is not leaking and I cannot find a part number to replace the hose barb fitting. If I could replace it then of course I would replace the banjo fittings

 

[Charles Erwin]

Your photo label refers to an 'inlet fuel barb.' This is the very same thing I called a 'banjo fitting' (because it is shaped like a banjo.) No need to replace the fitting - just the copper crush washers. I other words I think your inlet fuel barb crush washers are the source of the leak - not the hose clamp joint.

You might find your inlet fuel barb at Yanmar but not likely. However, generic inlet fuel barbs (banjo fittings) are available from an auto supply store like NAPA.

 

[pfaffk]

The light bulb just went on and I now understand what you mean by Banjo fitting. I will have to pull it off the engine and look for a replacement.

Thanks

 

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