Frequently Asked Fuel System Questions
Common questions about boat fuel systems, gasoline, additives and more. The FAQ section is still new and has a long way to go. Feel free to use the FAQ Submission Form, if you'd like to suggest a question that you feel should be covered here.
How long does it take for gasoline to go bad?
Do fuel stabilizers really work?
Should I store my boat with a full or empty fuel tank?
Which octane should I use?
My boat dies out at high speeds, but picks up if I squeeze the primer bulb. Why?
My boat dies out unless I hit the choke. Why?
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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. But... any service school I've ever been to, along with every manual I've ever read, basically said gasoline
should not be stored for over 60 days in ideal conditions. Hmm... Ideal conditions. Sitting in a hot metal
tank, in direct sunlight, is far from ideal. Ideal would be more like a nice cool tank that's buried underground.
Fuel stabilizers definitely help.
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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.
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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
lubed.
Ideally, you would drain and clean the tank after a long storage period, which just isn't practical or possible
for most people.
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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.
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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.
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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.
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Disclaimer: Use this information 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... take it to a shop.
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