I just bought a used boat (for a steal if I can get the engine working) and am having trouble with it running.  It's been sitting for almost two years and I think the gas is bad. I have tried siphoning it but I don't think that's getting all the gunk out.


Is there a better way to get this old gas out of the tank? Without sawzalling a hole in the floor and taking the tank out of the hull?  I tried running it out, first attempt, boat ran at full throttle for about ten minutes. Then wouldn't run at more than 15% throttle. Ran half the gas out that way.

Changed the fuel filter and filled up with premium fuel. Today it ran about an hour and a half at full throttle and then started struggling again.  I'm back down to half tank but don't want to run the rest out.

Any ideas?


Crash.

Drop a match in it.

Sorry, couldn't resist.

What about one of those pumps that boats have to pump water out of the boat?

Try overton.com.  They have a pump to use for changing oil in boats and carr. Should also work for this.  It comes with different sized attachements and is easy to use.  We used it to pump antifreeze out of a boat motor that was winterized.  Worked great.

Take off the gas cap and turn the boat upside down.

I hate to tell you this, but take it to a boaT/marine repair shop.  Not only will they get the gas out for you but they'll get the engine tweaked so you won't have to worry it's gonna konk out on you while your are in the middle of the lake.

Worth a little extra $$ IMHO

If it's an outboard disconnect from the main tank and run it on a small portable tank with good gasoline.

Try and find out if the tank in the boat is a steel or aluminium tank.  If steel you are going to have rust issues, and replacement is about the only option at that point.  You can get a matching tank thru West Marine's website  pretty easily.

As for emptying the tank,  disconnect the fuel lane between the fuel pump and carb and run the hose into a drain tank or bucket,  let the battery pump it out. Another option is to take the fuel line directly off the tank fitting and siphon from there.  

A good idea would be, once you get all that stuff out,  to put an inline fuel filter into the line before the fuel pump.  They have quick-change types  and water separators that are  inexpensive and easy to mount. Mine cost 32$ and catches an amazing amount of crud.

How about those fuel conditioners they sell for gas. Might work for you.
You'd be surprised to find that there's probably more water in the tank than gasoline from condensation.

Its PRI-G, the manufacturer claims that you rehabiilatate old fuel. Do a Goggle search. There was a discussion about gasoline preservation on the Survival Forum.