Unequal fuel burn

Descant · 08-13-2015, 02:15 PM

Idle is about the same. I'll have to look harder at the possible leak. The fuel gauges are also close (new senders this winter.) I also wonder about the flow between tanks. I don't have a transfer pump, but is it possible the balance flows mostly in one direction?

Looks like I'll have to spend some time next to the engines when we get a cool day.

Paugus Bay Resident · 08-14-2015, 07:40 AM

I'd check the fuel return lines. Sometimes they are plumbed to go to one tank, sometimes directly back to the injectors. Maybe there's some funky plumbing going on.

bilproject · 08-14-2015, 08:30 AM

Usually in a twin tank set up fuel is drawn from one tank and the other is connected to the tank being drawn from. as some fuel is drawn out of the tank by the engines fuel from the connected tank is siphoned over to the supply tank. Since there is a check between them the connected tank drains while the supply tank stays relatively full. There is also only one fuel gauge in the system and that is in the supply tank. See if that is not your set up.

08-13-2015, 02:15 PM	#1
Descant Senior Member Join Date: Mar 2006 Location: Merrimack and Welch Island Posts: 4,598 Thanks: 1,418 Thanked 1,705 Times in 1,109 Posts	Idle vs. leak Idle is about the same. I'll have to look harder at the possible leak. The fuel gauges are also close (new senders this winter.) I also wonder about the flow between tanks. I don't have a transfer pump, but is it possible the balance flows mostly in one direction? Looks like I'll have to spend some time next to the engines when we get a cool day.

08-14-2015, 08:30 AM	#3
bilproject Senior Member Join Date: Oct 2007 Location: Bear Island/Fort Myers, Fla Posts: 231 Blog Entries: 1 Thanks: 1 Thanked 59 Times in 41 Posts	check fuel line piping Usually in a twin tank set up fuel is drawn from one tank and the other is connected to the tank being drawn from. as some fuel is drawn out of the tank by the engines fuel from the connected tank is siphoned over to the supply tank. Since there is a check between them the connected tank drains while the supply tank stays relatively full. There is also only one fuel gauge in the system and that is in the supply tank. See if that is not your set up.

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08-14-2015, 07:40 AM	#2
Paugus Bay Resident Senior Member Join Date: Sep 2003 Location: Gilmanton, NH Posts: 754 Thanks: 135 Thanked 93 Times in 51 Posts	I'd check the fuel return lines. Sometimes they are plumbed to go to one tank, sometimes directly back to the injectors. Maybe there's some funky plumbing going on.