1995 355 Aft Cab, Aft fuel tank

[glazingguru]

I recently purchaced a 1995 355 aft cabin, gas engines. The previous owner stated that he never bothered to use the rear (aux) tank. I have been reading horror stories of unused fuel tanks and in this instance, the swim deck needs to be torn up to replace the aft tank.
I am not sure if the tank is okay or not.
I have a few questions that I am hoping someone here can answer.
1. Is there an easy way to see if the tank is still good without taking a chance on fouling the engines?
2. Do both engines draw from the rear tank until it is empty and then from the side tanks? I see no mechanical switch for the aux. tank.
3. If #2 is correct, it would be fair to assume the rear tank is empty... right?

Your comments/experience is appreciated.

[g36]

i have a carver 405 which is a bit larger but basically the same boat.
i have 2 tanks exactly where you are speaking about. unless the previous owner did some fuel line redesign there is a mechanical valve to switch the tanks from aft to saddle somewhere. there wont be an automatic valve for this. my valves are in the engine room aft wall, there is one for each engine. i know your engine room isnt as large as mine but you should be able to follow the fuel lines and see where they go to find the valves.
what does the aft fuel tank guage read? empty full?
if you want to know the quality of the fuel in the tank/s you could temporarily insert a small universal electric fuel pump (available at any autozone etc, about $35 )on the pick up line and pump out some fuel and check it in a glass jar etc. this will tell you if you have water and you will also be able to see if you pull out a bunch of crap once it settles. are you planning on using the tanks? if so you could also empty them out this way. in order to put in some new gas.

[Ramsport47]

The fuel valves in the 355/356 are at the front of the engine room, in front of the port engine. Mechanical as g36 stated. Most people do not bother to use the aft tank and either just leave it full or never fill it. There should be a gauge on the helm with a switch for the "aux" tank...it will read one way, but not the other. If it doesn't read in either direction, odds are it is empty...a good thing in this case. The only way you can check the fuel in it, without running the engines, is to take a sample from the supply line...if possible, hook a primer bulb into the nipple and pump it out with that.