How to Hook Up Gas Tank to Outboard Motor

Avoiding and Bypassing Problems

With Your Outboard's Gas Tank

(DON'T TRY THIS AT HOME)

by Stan Matthews

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Professionals may insert a paper clip into the "ball valve" portion of this engine connection to check the system

Much has been written about the care of outboard engines, less about the lowly external gas tanks that feed them. This article deals with that little red plastic container that holds the gas for your outboard, and the hose that delivers the gas to your engine. Without sounding presumptuous, you'll likely learn something here that will come in handy. The tips contained in this article may just help you keep your outboard running if fuel from your external gas tank stops flowing.

Despite the fact that this article discusses supplying gas to an engine, I will not discuss running out of gas…a problem best prevented by using the same principle airplane pilots do to assure their adequate fuel supply. Pilots calculate what they'll need for a particular trip, and plan to land with one third remaining in the tank.

The lessons below have been learned the hard way, by having to row distances in the noon sun, against current and wind, despite having enough fuel onboard to keep a perfectly functioning outboard engine running. The problems described below are particularly troublesome because they often cause an engine to stall only after it has idled and run long enough to travel up to a quarter of a mile into open water.

Problem No. 1- Wrong-Way Directional Flow Hose

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This hand pump will only work if its arrow points in the direction of gas flow AND it is pumped in the "up" position (as shown)

Every fuel hose that connects an external gas tank to an outboard engine has an arrow printed on its hand pump (that small bladder that contains a check valve and sends fuel from tank to engine with a few squeezes). At the beginning of each season, or whenever the hose is connected to its tank, make sure the arrow points in the direction fuel must flow…from tank to engine. Sounds too simple to mention, huh? Think again. It happened to me when someone I trusted set up my dinghy. The clue to solving this fuel supply problem is noticing that the hand pump does not fill with fuel after a "squeeze" is released. In such a case the hose is clogged, or the check valve inside the bulb is faulty, or the hose is installed backwards. Look for the flow direction arrow each time you install a fuel tank hose.

Problem No. 2-Malfuntion of Hose Check Valve

Most boaters are unaware that the check valve in a fuel hose's hand pump is designed to operate ONLY when the directional arrow is "up". I've seen many boaters climb into a run-about or dinghy, give a horizontal (or "upside-down") fuel hose hand pump a few squeezes, and take off. Unfortunately, if air has entered the line after sitting a while, the engine may start but will stall within a minute or two. The only way to assure that the fuel hose has been properly primed with gas is to raise the bulb so the check valve arrow points up, then do the squeezing. Enough said.

Checking for and bypassing a Defective Check Valve (a metal clipper, a paper clip, and "siphoning" always works-keep these items handy)

Let's say your fuel hose is properly connected to tank and engine, yet the hand pump does not "pressurize" the hose. If there's fuel in the tank the problem may be a faulty check valve. You can check the patency of the hose, and the check valve's function, by doing the following:

1. Remove the fuel hose's engine connector from the engine and stick one end of a paper clip into the steel ball end. This will open the connector to air

1. Remove the tank connector plug from the hose (you'll probably need a wire cutter to remove the small metal hose clamp)

1. Squeeze the hand pump and feel for suction at the tank end of the hose with your finger. No suction means a faulty check valve.

A faulty check valve may be bypassed by utilizing the natural phenomenon referred to as a siphon. To accomplish this one would open the fuel tank and place the fuel hose (having removed its connector from the hose) directly into the gas. Now comes the difficult, and potentially dangerous, part. We not only don't recommend this, but we strongly advise against using this technique. It is mentioned here strictly for informational purposes, as some professionals report using this technique. Siphoning gas can cause gas to enter your mouth and lungs and can cause serious injury and death! DO NOT siphon gas. That being said, professionals report placing the mouth on the engine end of the hose (which has been placed lower than the gas) and "sucking" fuel into the gas hose. Once the gas has passed through a portion of the hose the operator releases suction. Fuel then flows through the hose, priming it for connection with the engine. A quick pull of the paper clip would then make the engine connector end of the hose ready for attachment to the engine. The engine's fuel pump would pull fuel, and the engine should run, as long as the tank end of the hose remains submerged in gas.

Even when employed by professionals the above process is not only dangerous, but also potentially polluting to the environment. Plenty of rags must be on hand to mop up gas that spills during the siphoning process.

Problem No. 3-Malfunction of Gas Tank Hardware

Faulty gas tank connector. Valve should open with pressure on the pin. In this case the pin is frozen closed.

Occasionally the connector attached to the gas tank, the one that connects to the gas hose connector, is faulty. The spring on the valve can be checked manually by simply pressing in its pin, which should move in and out with moderate pressure. If either this connector is faulty, or if the pick-up hose inside the tank is blocked, then a professional, at his own risk, may choose to bypass the tank system completely and siphon gas from the tank (see precautions above).

No. 4(a)- Improper Tank Storage-Avoid storing an external fuel tank inside a boat

No one who has experienced a gas leak, and its potentially disastrous and fatal consequences, ever chooses to store a filled external gas tank aboard ship. Tank integrity diminishes over time, especially after years of being in the sun and under pressure. Valves and hoses can leak. Hoses can come apart from their connectors under pressure. As such, those in the know prefer to store fuel aboard a run-about or dinghy, and not on the mother ship.

No. 4(b)-Keep the Pressure Relief Valve Open

My closing comment comes from an old salt who runs an outboard engine repair shop on the north shore of Long Island, NY. After fifty years in the business, and despite his concerns that ethanol gas absorbs moisture when exposed to air, he strongly suggests keeping pressure relief valve's open. Why? He's seen tanks leak, or worse become explosive risks, as gas vapor becomes pressurized under a hot sun. Even though ethanol-containing gas can become fouled with water, he prefers to replace any contaminated fuel with fresh fuel rather than run the risk of leaks or explosion.  Having recently purchased a new external tank and had it, and its immediate successor, leak because of faulty construction, I am a convert and store our external fuel tank in the dinghy-with the its pressure relief valve cracked open.

Conclusion

Life on the water tends to be more enjoyable when an outboard engine runs well. Keeping the engine in good operating condition only assures that one part of the outboard's system works well. In addition to fresh, clean gas, it is best to know how to troubleshoot the connectors and hoses that supply fuel to the engine. Despite the fact that little goes wrong with external gas tanks, and their hoses, boaters are advised to become acquainted with their fuel supply hardware. As is usually the case in boating, a little knowledge and preparation goes a long way if and when something stops working.

How to Hook Up Gas Tank to Outboard Motor

Source: https://newsfromthebow.wordpress.com/2011/08/01/avoiding-and-bypassing-problems-with-your-outboard%E2%80%99s-gas-tank-don%E2%80%99t-try-this-at-home-by-stan-matthews/

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