Fuel gauges on the Carver 390 CPMY

I've seen several Carver with that gauge, but not with the aux. tank. How many gals is the Aux. tank? Sounds like just some extra gals. for if you go past 'E', but the gauge should be reading the port and stbd tanks, not the Aux. The Aux may only feed the port motor as a get home measure. Odd configuration if that's the case.

My old '96 355 Aft Cabin had the same arrangement--3 tanks, 2 fuel gauges, 1 of which was shared by 2 tanks and controlled by a toggle switch.

My 356 is also like trmnewt. The right side of the dash has a toggle that reads port and starboard. When you hold it to either side the gauge shows the fuel in the corresponding tank. The Aux tank toggle is on the left side of the panel. You need to open the bilge to switch tanks manually between the hangers (port and starboard ) and the aux (rear). To be clear...your 390 does not have a switch that toggles b/w the two ?

Try that port/aux switch as a toggle. I can't imaging that the there is not a gauge reading for each tank. For pure safety reasons you need to know how much fuel you have at all times. Somethings not adding up. What year is the boat. Maybe post a picture of the dash and the switches. Would love to help.

One other quick thought. Assuming all are full, I run from the side tanks first, until half full or so. Then switch to the stern tank.
If you run from the stern tank first, you will soon start to run bow heavy. Definitely keep the stern tank in the
rotation, so as to keep fresh fuel in the system.

+1 bucketlist. My 355 had fuel levers under the salon sole for each engine. Could select port, starboard, or aux for each. I used to run each engine off the tank on it's side, and if necessary switch both to aux.

On a boat like the carver, most of them run stern heavy and it would probably run faster and help it stay on plane by draining the cockpit first. Now in rough seas, you're better off draining the foward tanks first.

Do the 2 tanks in the engine room have a hose at the bottom of the tank, running from one side to the other, to equalize them? If in fact they do, then you only need one gauge as they'll equalize the level in them.

Mine didn't have a hose or equalizer pump. My boating at the time was primarily inland lakes, so boat trim was not so much of an issue.

I have no experience with a Carver 390 CPMY, but if you can see the fuel tanks, you could look for a wire connected to the port tank. That would let you know whether the port tank was intended to be "gauged" or not.

It is vital that all tanks are gauged. My carver draws fuel from the port tank for the generator. This will cause unequal amounts in the hanger tanks. This is important info. What year is your 390?

My 2003 404 CMY has 3 tanks---98 gal port, 98 gal starboard, and 120 under the cockpit(AUX). There are 2 "FUEL" switches with corresponding fuel gages, one on each side of the helm----switch on left panel is AUX. Turn it to the left, it shows aft tank level. Switch and gage on right panel is PORT/STARBOARD. Turn switch left, it shows PORT tank level. Turn switch right, it shows STARBOARD tank level. As far as I know(I sold Carvers for 15 years), all of these boats have the same setup, from the 1994 390 CMY, to the newer 400 CMY, to the final version, the 404 CMY. If not set up like this, something must have been changed or something doesn't work properly anymore and needs repair. I hope this helps. Cheers.