Fuel tank design

[DannyS]

This post is related to the Gasoline in Diesel thread that I posted a couple of days ago. The boat is an O'day 35 and I decided to inspect the fuel pick up tube inside the fuel tank because I'm getting a very rapid clicking from the Facet fuel pump that would indicate that there might be air in the system. I've isolated the possible air infiltration to the tank because when I got the engine back up and running, I used a small auxiliary fuel tank to supply fuel to the engine and the clicking was slow and steady which is what I'm used to with the system. However, when I removed the 90 degree fitting on the tank, I was surprised to find that the pick up tube was not attached to the fitting, it is welded into the tank and is not removable. Does this seem an odd way to design a tank? My thought is that perhaps the pick up tube might have cracked and is allowing air to enter from the air cavity in top portion of the fuel tank.
Thoughts?

 

[SG]

NFIW

https://www.amazon.com/s/?ie=UTF8&k...t=&hvlocphy=9061285&hvtargid=kwd-297958927347

 

[Ken Cross]

Makes sense, cap it off and put in a new one.

Ken

 

[JimInPB]

In tanks with welded-in pick up tubes, I have sometimes made repairs by tapping a 1/4" NPT female in the tank, then soldering a piece of 1/4" copper refrigeration tube into a brass 1/4"NPTm x hose barb adapter. The copper tube gets bent to fit into a corner of the tank & becomes the new pick up. This only works well in tanks that have a consistent low spot where the fuel pools.

 

[Gunni]

Never heard of a welded-in pickup tube, can’t even understand the logic. Got any pictures?

 

[capta]

Couldn't you just have a ¼" copper tube of the appropriate length braised into the 90-degree fitting? Just ignore the old tube.

 

[DannyS]

NFIW

National Federation of Indian Women? That's all I found when I googled it.

 

[SG]

No ____ Idea Why

I still very fondly remember sailing in the Apostle Islands many, many, years ago.

 

[DannyS]

Makes sense, cap it off and put in a new one.

Ken

Unfortunately, the tank is buried under the cockpit with only about 5 or 6 inches of space above it.

 

[DannyS]

Couldn't you just have a ¼" copper tube of the appropriate length braised into the 90-degree fitting? Just ignore the old tube.

I thought about this as an option and still may try it. It would have to be the flexible copper tubing since I don't have much overhead clearance above the tank.

 

[SG]

Unfortunately, the tank is buried under the cockpit with only about 5 or 6 inches of space above it.

What inside diameter is the tube that that is soldered or welded in there? (can you insert a tube within it?
Is there an access plate? Do you have room to cut it off?

 

[DannyS]

What inside diameter is the tube that that is soldered or welded in there? (can you insert a tube within it?
Is there an access plate? Do you have room to cut it off?

It's a pretty large inside diameter, at least 1/2", maybe 9/16"? My thought was to either solder a barbed fitting to the 90 degree fitting and attach a hose of some sort to it or solder a soft copper tube to the fitting and just run it inside the existing pick up tube. No access plate.

 

[SG]

Careful with any flame around that tank.

Does the existing 90 degree fitting have a threaded fitting and then a barb for the fuel hose?

Now is the time for some PHOTOs. ;^)))

 

[capta]

I thought about this as an option and still may try it. It would have to be the flexible copper tubing since I don't have much overhead clearance above the tank.

If it was me, I would cut a small hatch above where this tube must go, and not have a flexible one.