Not possible But True

[JLR]

Just took first leg of summer cruise. Four fuel tanks. Despite fuel manifold on port engine being in correct position, upon arrival, gauges show both engines drew from same fuel tank. Checked with Bruce. There is no cross over, other than the fuel manifolds, which would permit both engines to draw from same tank. Three of four tanks show full and fourth tank shows double the usage (I.e. as if both were drawing from that same tank). Is there any reason why on a fuel manifold, the handles should be turned in only one direction ( clockwise or counter clockwise) for the manifold to work? It would indeed seem odd that the supply handle was off by 180 degrees but the return was correct. To my knowledge, there has been no change in the handles, like one falling off and being reinstalled up side down. I see no evidence of fuel out the vent on the return side assuming I was drawing from one and returning back into a tank that was full. Any ideas would be greatly appreciated. Also, is there a way to visually check the setting of the manifold other than by the marking on the front of it? In other words, can I remove the marking plate and eyeball the actual manifold to verify positions. Pretty well stumped on this one. Thanks.

 

[Timeout]

Could you be drawing out of both tanks but returning to one?

 

[bobk]

How about the gauges? Could one have failed in a position reading full?

If you drew from two tanks and returned to one, Detroits would have transferred enough fuel that it would be running out the vent.

To your question about the valves, assuming they are typical ball valves, how you get to the position they are in should not matter. Can you remove the gage senders and sound the tanks with a rod?

Bobk

 

[JLR]

All good thoughts but triple checked position of handles and they appear to be correct as far as markings go. I thought about both drawing from one and then having one return to another full tank but no obvious signs of fuel out the vent. I will need to check at the dock for sure. I do not think I can easily check fuel levels manually but there is no doubt that one tank reads full that should read one half and other reads in reserve that should also read one half.

 

[JLR]

Is there any way to verify the position of the ball valve selector without using the labeling on the plate. I still think my supply selector handle is off by 180 degrees.

 

[Avenger]

The only thing I can suggest is take the nut off and see if somebody was swift enough to make some witness marks. OTOH, if they were swift enough the handle probably wouldn't be backwards.

 

[JLR]

Thanks. Fueled up yesterday and verified gauges are accurate. Both motors pulled off one tank and likely returned to same tank as well as I see no obvious signs of fuel out the vents. Now to pull handles and check for marks.

 

[rsmith]

Your going to need to pull the connections at the tanks and back pressure the system some how with a prime pump or some thing to be sure. Maybe the valves were replaced and someone screwed up the connections.

 

[JLR]

Mystery deepens. Thanks to help from Bruce Morrison, I have now verified through markings on the stems of the manifolds that port engine should be drawing and returning to the mid fwd tank and strbd engine should be drawing and returning to the mid aft tank. Problem is, they both draw and return to the mid aft tank. So, it does not appear to be a problem with the manifolds unless the stems broke inside on two manifolds. Unlikely. They worked perfectly for the 1200 mile trip North and now the laws of physics cease to exist aboard the boat. Assuming manifolds are correct and no master crossover valve, how is this possible?

 

[SportFishCruising]

Mystery deepens.... the laws of physics cease to exist aboard the boat.

sorry... I had to lol at that one

 

[JLR]

No pride of authorship- comes from My Cousin Vinny movie. So, unless this. Is a " magic" manifold, I am stumped.

 

[JLR]

After speaking with Bruce, Roger and the manufacturer of the selector valve, I have decided to go ahead and replace both the port supply and port return valves. Both the handles and the actual Hatteras mark on the stems themselves indicate fuel flow should be from a tank other than the one being drawn and returned to. It would be a really odd coincidence if both valves went at the same time but it seems like the right, but expensive place, to start.

 

[JLR]

I just wanted to bring this full circle for anyone who may have a similar issue. It appears as this issue has magically repaired itself. On the way back from my summer trip, the fuel selector valves (supply and return) on the port engine worked perfectly. The only thing I can think of is that exercising the ball valves in the selector valves has freed them up to work as they were designed to work and as they are labelled. No repair needed at this point.