Frequently Asked Fuel System Questions

How long does it take for gasoline to go bad?

There are several things that come into play here: temperature, humidity, fuel quality, additives and many others.

Most sources state that gasoline should not be stored for over 60 days in ideal conditions.

Ideal conditions.

Ideal conditions would be in a nice cool tank underground. Sitting in a hot metal tank, in direct sunlight, is far from ideal. In any case, fuel stabilizers definitely help.

Back to Top

Do fuel stabilizers really work?

Sure, but only when added to fresh fuel; they do not bring bad gas back to life. Fresh fuel is always the way to go, but properly stored, treated fuel usually won't cause any problems. It's still a good idea to dilute it with fresh fuel, if you have room in the tank.

Also, be sure that you're using a fuel stabilizer. Bottles marked fuel treatment might not be what you're looking for. Read the label on the bottle, just to be sure.

Back to Top

Should I store my boat with a full or empty fuel tank?

Fill the tank with a fresh fuel & stabilizer mix. Keeping it full helps prevent moisture problems from condensation and can also prevent corrosion inside the tank in salt water environments. It also keeps the fuel gauge sender lubricated.

Ideally, you would drain and clean the tank after a long storage period, which just isn't practical or possible for most people, so keeping it full with a fresh stabilized fuel mix is the next best thing.

Back to Top

Which octane should I use?

Whichever one your manual recommends, of course. ;-) Eighty-seven is usually fine. The recommended octane is generally the lowest one that the motor will run on without pinging. Premium grades often burn cleaner because of higher detergency--not because of higher octane.

Back to Top

My boat dies out at high speeds, but picks up if I squeeze the primer bulb. Why?

In most cases, this indicates a faulty fuel pump--probably a pinhole in the diaphragm. Sometimes, the pump still supplies an adequate amount of fuel for idle/slow speed running, but starves for fuel at higher speeds. By squeezing the primer bulb, you're acting as a manual fuel pump. Any time you suspect a fuel problem, be sure to inspect the entire system.

Back to Top

My boat dies out unless I hit the choke. Why?

Usually, a clogged/dirty carburetor or a stuck float can be blamed for this. Any time one carb has to be cleaned and rebuilt, do the same to all of them. Be sure to inspect the entire fuel system to be sure there aren't any other problems.

Back to Top


Disclaimer: Use information on this page at your own risk. Seiler Marine is not responsible for the mechanical ability of others. Never attempt a repair without the proper tools and service manual. When it doubt, it's best to take it to a pro.