Fuel oil leak

[Mark Wagner]

I have always gotten great advice on this website. I have a 1985 Hunter 31 with a Yanmar 2GM20f diesel leak probably coming from the fuel oil return at the attachment to the fuel tank. I was dangling upside down tonight trying to track the leak down. Of course it seems to be coming from the most unaccessible corner of the fuel tank. Alternatively it could be from the fuel tank outlet or fuel tank filler junction at the fuel tank but I really didn't see signs in these areas. I guess it could be a leak in the fuel line, but that seems unlikely.

Has anybody had similar experience? Additionally, has anyone replaced this type of fitting that attaches to the fuel tank and where do you get one. Looks like a nut at the base with a barbed fitting. I wonder if this screws in or if I remove it, if there is a nut on the inside will fall down into the tank.

Many thanks in advance for advice. Mark

 

[woodster]

look for fitting on best fab site they have what you are looking for and no there will be no nut fall off when you remove the old one but you may have a tank leak that tank is very old and could have a pin hole in it clean everything very well and dont run the engine a watch to see if you have any seepage from the tank and if not run the engine and see if you have evidence of a leak at that fitting but first clean everything up so you can tell where it may be

 

[Mark Wagner]

Thanks for the advice Woody. I was to discover that the fitting that goes thru the polypropline tank with only one nut on the outside is called a "bulk blind tank fitting." It is kind of like the expandable dry wall bolt. I was also to discover that the fitting that attaches to the bulk blind tank fitting had rusted and broke off leaving the fuel return hose dribbling diesel on the top of my fuel tank (see photo). Depending on how the boat healed, fuel would appear in odd spots. Of course the hard part was getting in to make this observations. I had to dismantle much of my aft section to get my head and hands in to discover the problem.

 

[RoyS]

The fitting you need is readily available. I recommend that you get a fuel fitting with a pick-up tube that extends to the bottom of the tank. Even though this is a fuel return line, some engines drain back fuel through the delivery side by drawing air in the return side. Both ends should have a pick-up tube to eliminate this problem.

 

[Ken13559]

Looks like either a 1/8" or 1/4" NPT thread.

 

[HMT2]

Mark, nice work! That spot looks familiar to me, makes me ache just thinking of the contorshuns I made to get there.

 

[Jackdaw]

look for fitting on best fab site they have what you are looking for and no there will be no nut fall off when you remove the old one but you may have a tank leak that tank is very old and could have a pin hole in it clean everything very well and dont run the engine a watch to see if you have any seepage from the tank and if not run the engine and see if you have evidence of a leak at that fitting but first clean everything up so you can tell where it may be

Woody, did you break your period key?? ;^)

 

[woodster]

no Jack .... but i forgot to use it lol ....you know i do have the best forgetter in the world... period.... lol