I have a 4 stroke, 130 horse Honda on my boat. It has been sitting the past 5 months. The question is does anyone know if I should be concerned about the 25 gallons of fuel that has been sitting? Should I have it pumped out, or do you think I am OK? Thanks!

It'll be fine. If you're worried, though, you could get some of that fuel dryer stuff and dump it in. That should help dry up any water that's condensed in there.

It won't be fine, unless you added fuel stabilizer when the boat went into storage. Gasoline undergoes chemical reactions. Water is not the only problem with old gas. It is also new hydrocarbons that have different combustibility properties, that can cause detonation. It's no use adding stabilizer now, as that prevents the decomposition but doesn't reverse it.

I would remove the fuel, and burn it in your truck, 5 gal at a time on a full tank of fresh gas.

I can't even begin to think how much it would cost to have that Honda rebuilt because of a detonated piston .

I dunno, I've left fuel in many vehicles for over 6 months and never had a problem. From boats to cars to pickups to bikes. I know the octane level diminished, but the vehicle still ran fine. I always try to ensure the tank is topped off before long storage, too. Matter of fact, my dealer said to ensure you have fuel left in the system so the seals and what-not don't dry out.

Of course your mileage may vary.

It depends on the nature of the vehicle. Certainly, a Briggs-n-Stratton lawn mower engine can choke down some pretty polluted fuel. Modern car and truck engines have an array of sensors that adjust the timing and a bunch of other stuff to accommodate the fuel. Boat engines, even Honda, aren't as sophisticated, even if they have as their basis the same block. I would imagine the Honda 130 runs a fairly high compression ratio and its runtime parameters are pretty close to design limits, so you are in the danger zone.

Given the cost of outboard repairs, I think it would be wise to replace the fuel. Even if the motor is under warranty, I bet they could back out if they find out the fuel was 5 months old.

Thanks for the input. Sounds like one of those better safe than sorry scenarios

Replace the fuel

I'll bet alot of marina gas has set in a tank more then 5 months, if you have a fuel/water seperator I wouldn't worry about it, if not throw in some Water Zorb or Stabil.

Next time use a fuel stabilizer before storage.

Old fuel I would not run.

Old fuel in a outboard is evil stuff. I would get it out and use it in your car or lawnmwer, as previously suggested. Someday you may need that motor to get you out of serious trouble, and it needs to be reliable.

I've got to work with the stuff everyday......pump the old fuel out and start anew. It's easier to get a tow on dry land than on the water.

Robert