clean out of long un-used aux. fuel tank and other fuel tank

[glazingguru]

Hi,
I think I saw this subject once before, and possibly a great solution, but can't find it.
I have a 1995 355 Aft Cabin with gas engines. I have owned the boat for a year. The previous owner never used the aux. tank and in fear, I have not either. Is there a fairly simple way to clean out any debris that might be there so that I can use the tank?
Also, can anyone tell me exactly how the aux tank works? as in, will the fuel be used automatically from the aux tank before the fuel in the main tanks is used?
Also, can someone explain how the syncronizer works? there is a guage and a switch.

[Lyndon670]

Are you speaking of the one in the swim platform?

[glazingguru]

yes. In the swim platform. 68 gallon aux. tank

[Lyndon670]

You may want to check the tank first. Those aft tanks were known to leak in many occurrences. Might be why the P.O. didn't use it. It's very common, I have helped repair 2 in the last 5 years. If you google it, you should see some results re leaks.

[glazingguru]

okay, how would I "Check it"

[Lyndon670]

Checking it needs to be done on the hard. You need to cut a couple of inspection holes in the underneath of the platform. With a small amount of fuel in the tank (less than a gallon), you should be able to smell the fuel via the inspection holes after an hour or so. The leaks aren't typical leaks, but are "weld weaps". While you are doing this, lift all the floorboards in the aft stateroom and lift the mattress and the access ports under the bed.

You might think this is too much work, but trust me - the other way to find out they leak is to turn the valve in the engine room, fill them and loose all your fuel in the aft tank, and virtually never get the smell if gas out of your back stateroom again.