Recently, I watched as one of my dock neighbors walked down to his boat. Within seconds of stepping aboard, he stuck the key in the ignition and started it up. His boat is a bow rider with an inboard engine and stern drive. It made me wonder how many people start their boat’s engine without even a thought of running the blower beforehand.

If you are one of those people, consider this: According to the U.S. Coast Guard, there were 176 incidents of fuel-related boat explosions in the U.S. in 2020. Most of these incidents could have been prevented if the operator had simply taken a few minutes to run the blower prior to turning the key. All gasoline-powered boats equipped with inboard engines and built after July 31, 1981 are required to have a blower installed. It is recommended that this blower be run at least four minutes prior to starting the engine. It should also be on while running the engine at idle or no-wake speeds for long periods of time.

So what does this blower thing do anyway? Basically, the blower is used to ensure adequate ventilation in the engine compartment. It is a fan that will run, sucking air in one side of the compartment and blowing it out the other. By doing so, any gasoline fumes that may have built up in the compartment will be ventilated into the atmosphere prior to starting the engine.

So why are there fumes in the engine compartment anyway?  Technically, under normal conditions, there should not be.  Sometimes conditions are not normal though. Maybe a fuel hose has come loose over time due to vibrations or maybe there is a defect in the fuel pump. Something could happen that may cause a small amount of fuel to leak into the bottom of the bilge. As it evaporates, fumes build up in the engine compartment. A spark from an electrical wire or a backfire from the engine can then lead to catastrophic results.

Personal Watercraft have an enclosed engine compartment. You may ask why they do not have blowers. PWCs do have a passive ventilation system but they are clearly not as effective as the blower on a boat. That is why PWC manufacturers recommend removing the seat to expose the engine compartment and checking for fumes before starting the machine.  It is a common understanding that the best way to detect gas fumes is by using your nose. In fact, this method can be used no matter what type of vessel you are operating.

So if this is so important, why do I not have to run a blower on my car before starting it every morning? Unlike boats, cars do not have an enclosed engine compartment. If a leak did develop due to a faulty fuel line or some other anomaly, the fuel would simply leak onto the ground below and not remain in the engine compartment.  This in combination with the ability for air to freely flow through the engine area would prevent any potential explosion hazard.

The next time you take your boat out for a day on the water, don’t forget to flip that blower switch and let it do its job before turning that key.

We all love being on the water and can’t wait to get out there but four minutes is more than worth it to ensure a safe day of boating.