fuel gauge /fill situation??? a little confused

[guglielmo6160]

ok fellas, I have another observation, /question. as you all know I have been fooling around with my gas tanks , valves etc, and I just noticed something which is kinda weird to me. Im going to try to explain, without confusing everyone so here goes.
The port fuel tank fill supplies fuel to the foward fuel tank, the starboard guel tank fill supplies fuel to the aft tank. Ok, pretty simple, so when your pumping gas , your filling the foward tank from the port fill and the tank right behind that one is filled using the starboard fill. Ok that I know.
next the fuel is supplies from each of those two tanks through two copper tubes coming through the bulkhead, each tank has its own valve at the exit of the tank, so to recap, each fuel tank can be shut off and turned on , directly at the exit of the tube which comes out of the tank,. ok, hope your all with me still. when both the tubes exit through the bulkheasd , inbetween them they add a cross over tube, with a valve on it as well, so when all valves are open, everything is open and fuel can travel freely where ever. Ok............
the fuel transmitters in the tanks tie to the gauges at the helm. right? but the issue is, there is no way to direct fuel from the port tank to the port engine , exclusively and vice versa, the only thing you can do is direct all the fuel from the foward tank, to both engines, or the rearward tank to both engines, . you basically cant feed port engine from the port gauge or the starboard engine from the starboard gauge
this of course is from the placement of the gate valves that were I believe factory installed, any thoughts ? this makes no sense, to me, there cris crossed at the helm. Im sure youll get a kick out of my drawings,,lol,

[img][img]http://i362.photobucket.com/albums/oo63 ... 0_0835.jpg[/img][/img]

[prowlersfish]

Someone crossed the wire at the dash or tanks at some point in time . I would just switch them back and be done with it

[gjrylands]

The set up is a bit weird. I believe my 69 31’ Trojan was set up the same way. The way you described and drew it, your starboard engine draws fuel from the tank that was filled on the port side, and the starboard gauges is reading the level of the tank that was filled on the starboard side, but is fueling the port engine.

I think this was the way Trojan plumbed the system. As you know the fill pipe is on the opposite side of the tank then the pick up tube and fuel level sensor. To make the most direct route with the fuel lines Trojan chose to feed the port and starboard engines from the pick up tube that was the closest to the engine. Trojan made the gauges show the level of fuel that is in the tank filled on that side of the boat. In other words, if the port gauge is reading ½, and the starboard is reading ¼, you would expect to put more fuel in the starboard side of the boat even though it is fueling the port engine.

[guglielmo6160]

Paul

I thought of that, but wouldnt that mean the fuel fills were backwards to?

[gjrylands]

Someone crossed the wire at the dash or tanks at some point in time . I would just switch them back and be done with it

I think this is the way Trojan did it originally. You could cross the wires but you would have to know that you fill the starboard engine from the port side, and visa versa.

[guglielmo6160]

ok, thats what I figured, just seemed strange to me they would do it that way. thought I was loosing it, you see what would happen is , i was leaving all the valves open, and for some reason the rear tank would empty out faster than the foward tank, therefore creating air in the tubes shutting down the engines, I guess the pumps would opt to suck the air rather than the liquid, what Im doing now is running the both engines via electric pumps on one tank or the other, not both at once, when I notice the one tank lowering I can divert to the other and close the one off thats low,


yeah I know < I have alot of free time,,,

[prowlersfish]

You could switch around the fuel lines but that would make for some long lines .

[guglielmo6160]

nah, as long as you guys think thats the way Trojan did it, thats fine with me, I just thought somewhere along the line someone messed with it, I think as girylands says, they did it for a more "direct " route


its just wacky

[Dan Faith]

A strange set up, my tank set up on my F30 sport fisherman is the same but they do fill port engine on port side and starboard engine on the starboard side. The crossover valve is always closed except in an emergency (out of fuel in one tank) running with crossover open will as you discovered drain one tank faster then since air is easier to pull than fuel both engines will quit. Has a friend discover this the expensive way (had to be towed and found out he had plenty of fuel) When the empty tank was refilled both engines ran great it happened twice before he discovered the problem.

[guglielmo6160]

funny you mentiion that Dan, the EXACT same thing happened to me. so what I think Im going to do is if you look at my fancy diagram above, I will leave the valve open that crosses between the two engines, on the other side of the bulkhead and shut down one tank at a time so both engines will draw from which ever tank I choose.

[Dan Faith]

That is the same way I do fuel management in my airplane. I never draw from both tanks at the same time plus I use time and alternate every hour tank to tank (this keeps the load level, something we generally do not have to think about in a boat) not as critical. One difference is I generally on a trip always begin with full tanks.

[1967 seavoyager]

My tanks are set up like yours. Starboard fill is for the Port tank & gauge & vice versa. Then there's a crossover line to run the generator from either tank & 3 filters.

[guglielmo6160]

where would the cross over line be located, I dont see one, as there was a generator inbetween the engines originally but long removed, so at some point it was redone, how should it have been as I think Im still having issues with this fuel line set up.