Air in fuel feed

[dehler25]

I built a fuel polisher sometime back and the pump failed. I replaced and because I used clear fuel line I was seeing air streaming through, not a lot but intermittent. I replaced most fuel lines with clear to see where it was entering as every other means to stop it failed. I tracked back to the fitting on the tank which is a square block threaded into a large nut which I resealed the adapter fitting and barb. The tank is almost full so the air must be entering above the fuel level. Anyone ever have a crack or such at the pick up tube? I am going to pull the tube to inspect, but haven't done so yet. I am hesitant because the tank is fiberglass and the fitting is substantial.

 

[JoeWhite]

Yes I have heard of a pin hole on the pickup tube above the fuel level.

 

[dehler25]

Either this has never happened to any one or no one is aware, that is the magic of transparent fuel line, it gives you something to worry about.

 

[Project_Mayhem]

Did you bleed the fuel system properly after servicing it?

 

[dehler25]

Did you bleed the fuel system properly after servicing it?

It is air coming up the feed from the tank

 

[dehler25]

Yes I have heard of a pin hole on the pickup tube above the fuel level.

Took a while to get back, thanks for the response. I pulled the insert adapter that threads into the large nut on the tank, it has a flare that appears to pressure fit the dip tube, my concern is I have never seen how that is assembled. Can I remove the large nut without the dip tube dropping into the tank as it would be v e r y difficult to retrieve. Have you ever seen the assembly. I reattached the adapter and it seems worse than before. Are Catalinas similar ?

 

[JoeWhite]

I am not sure how the fixture is assembled on my fuel tank. If you are concerned that the tube may fall down into the tank, can you insert a springy wire with a hook at the end into the valve and down the tube about a foot so if it drops you can pull it up. An other idea is to use pipe cleaner with a long springy arm. I would think it is not going to drop down since it was installed that way. Is the fuel gauge access opening closeby? You may be able to hold the tube through this opening.
Post a few photo.

 

[dehler25]

I am not sure how the fixture is assembled on my fuel tank. If you are concerned that the tube may fall down into the tank, can you insert a springy wire with a hook at the end into the valve and down the tube about a foot so if it drops you can pull it up. An other idea is to use pipe cleaner with a long springy arm. I would think it is not going to drop down since it was installed that way. Is the fuel gauge access opening closeby? You may be able to hold the tube through this opening.
Post a few photo.

The Gauge opening is close, the tube would need to go close to the bottom of the tank and there is a separate generator pick up which I expect does not go to the bottom for a reserve. I admit i expected that removing the fitting would allow the dip tube to extract, I did not expect a flare fitting, I deal better with visuals too. I will take one in a couple of days when I get back to the boat.

 

[dehler25]

I am not sure how the fixture is assembled on my fuel tank. If you are concerned that the tube may fall down into the tank, can you insert a springy wire with a hook at the end into the valve and down the tube about a foot so if it drops you can pull it up. An other idea is to use pipe cleaner with a long springy arm. I would think it is not going to drop down since it was installed that way. Is the fuel gauge access opening closeby? You may be able to hold the tube through this opening.
Post a few photos
I get to wear the I'm really dumb sometimes hat! When I looked at the fitting it looked like a male flare and looking into the 1/2" opening I saw what appeared to be a female flare just below fuel level, turns out the fitting was simply a barb for a hose and the female flare I thought I saw was just the fuel meniscus, the hose had fallen off! The fuel level was high enough that it would draw as long as nothing moved. I made a new fuel line and no more bubbles. It could have been bad if I was not working on the polisher as the engine would have fuel starved with a full tank, thanks for the feedback.

 

[53neptuneman]

Do you have room above the engine for a day tank? That will give a solid flow to the engine. I pump my fuel from five fiberglass tanks. The transfer pump can pump fuel if there is some air in it. At times, I have had air from some of the intakes. It was the only way I solved this problem.

 

[jssailem]

Pictures are a big help. Air will find a way into your lines on the vacuum side of the lines. If you see bubbles then you have a leak as you have diagnosed.

It is possible to replace the dip tube. You can have a flare put on the dip tube if need it. Be sure the dip tube is at least an inch off of the bottom. Will lessen the chance for water and tank debris to be sucked up.