What can I use to clean out a tank that was used for a two stroke engine to be able to use it for my newer four stroke? Can I just use soap and water and then let it dry or should I use some sort of solvent? All replies appreciated.
This is no means an authoritative answer, but if it's in the boat I'd say empty it as much as possible, add fuel, slosh or spray walls if possible at all, remove and run through a vehicle, or lawn equipment, diluted. (if an older vehicle, diluted shouldn't hurt anything)
What size tank are you talking about and is it removable or out of the boat???
If it's removed or removable I'd say wash it/rinse it with dawn and water ???? rinse, rinse, rinse, and dry...
While it's out I'd say get it pressure tested too.
I wouldn't worry about pressure testing a portable tank, if it's not leaking it should be tight. A larger permanent mount type tank would be a better candidate for that. Steve is right, just slosh some fresh gas around in the drained tank, and run it through your lawnmower.
Pat in Joppa
If it's not ancient it's probably fine...if it's old, replace it. Pressure testing costs more than a replacement and it's as hackeyfly mentioned, intended for permanently installed tanks.
Since it's a six, you can basically do want ever you need to do with it.
If you have a lot of fuel in it that you can;t use up somehow you can dump it into a 5 gallons plastic jerry jugs and store until a hazardous waste day at you local landfill. ( I know Anne Arundel County had them periodically)
With the six you can empty it and wash with detergent, flush, dry and slosh with fuel, empty, and go fishing !!
Depending what engine your running it on, if it's fuel sensitive you can add an in-line filter.
I'm assuming this is gas left over from last year? I'd drain it out and put into another container , use it for the mower or put in your vehicle. Whatever you use it in make sure you are adding some fresh gas with it.