Two Lines from the Tank, 4JH2 Yanmar

[rebel heart]

So I was measuring out a project to install a T fitting in the fuel line for my diesel heater. T into the line between the tank and the secondary Racor's, and put a low pressure pump in that can fill a little ~3 gallon day tank which gravity feeds the diesel heater. I can already see some problems in regards to the lift pump sucking in air from the heater line, so maybe I'll do something else. Anyway...

There are two lines coming from my fuel tank. One is running to the secondary fuel filters (the Racors), which then of course lead to the primary, and on into the engine.

Oddly, there is another line which is also running from the primary fuel filter to the tank. There's no pump between the two, so I'm guessing it's maybe an overflow of some sort? Either way, just trying to figure this one out a bit.

Thanks so much!

[rebel heart]

Okay so I pieced through this and figure out that yeah, it's a return line. And that apparently it dribbles quite a bit. Good to know!

http://www.cruisersforum.com/forums/...ine-16186.html

So back to where I started. Will t'ing into the primary fuel line (from the tank, before the pump) possibly result in air bubbles? Running from the T to the heater there will be a low pressure fuel pump further up the line. I could install some sort of valve but I'm open for suggestions.

[daddle]

Basically anything else attached to that line from the tank doubles the risk of trouble. You'll probably be okay. Do very good tight work. Make the heater line loop lower than the bottom of the tank if you can.

[DeepFrz]

I recommend you do put a cut off valve on the heater line as well. It is always recommend though that you run a separate line to each device.

[rebel heart]

So if I loop the line below the bottom of the tank (should be easy to do), and put a shut off valve between the low pressure pump and the T (heater side of the T), that would be my best bet, short of running a new line?

I thought of T'ing into the return line, but I imagine the return line doesn't go to the bottom of the tank and just allows new fuel to drip down.

[DeepFrz]

You just need to run your line to about 1/2" from the bottom of the tank. No need for a loop.

Return lines "should" go to near the bottom of the tank but who knows what any particular installer has done.