Rajan Wilcox
If you're looking to convert a two-line fuel system, you'll need to understand the type of engine you're working with. For example, a 2-cycle engine has a sealed crankcase with alternating cycles of pressure and vacuum as the piston moves. This affects how the fuel/air mixture is drawn into and forced out of the crankcase. There are various methods for converting a two-line fuel system, depending on the vehicle. For instance, a 1958 18hp Johnson engine can be converted by using a sideplate with a fuel pump attached from a slightly newer model. Alternatively, you can use an adapter to convert without flaring the OEM hard line. It's also important to consider the materials used, as some fittings are illegal in certain places, and others may not withstand high pressure.
Characteristics and Values of Converting a 2-Line Fuel System
| Characteristics | Values |
|---|---|
| Why convert a 2-line fuel system? | To resolve starting issues, update old fuel systems, or combine two fuel systems into one. |
| Types of fuel systems | Return fuel system, returnless fuel system |
| Fuel line functions | The larger line is the main fuel line, the smaller line is the return line. |
| Fuel pump function | Runs at 100% all the time; the fuel pressure regulator determines how much fuel pressure is needed and sends excess back to the tank. |
| Fuel system components | Fuel tank, fuel lines, fuel pump, fuel filter, carburetor, pressure tank, check valves, fuel rail |
| Conversion process | Understand the 2-cycle engine, modify the intake manifold, tap into the bypass port cover, update fuel pump, change quick connector, flare fuel lines, use adapters or connectors |
| Tools and parts needed | Variable speed electric fuel pump, screwdriver, tubing, adapter, connector, cover, fuel pump gasket, aluminum rod, nuts, tubing adapter, tube sleeve, reducer, fuel filter, wrench, vice grips, Allen wrench |
| Considerations | Cost of new parts, safety standards for fuel lines, space constraints, difficulty of process, alternative methods |
Explore related products
$89.23 $102.99
What You'll Learn
Converting the Old OMC Dual Fuel
The process of converting an old OMC dual fuel system to a single-line setup involves several steps and modifications to the fuel lines, connectors, and tank. Here is a detailed guide on how to perform this conversion:
Understanding the 2-Cycle Engine:
To begin the conversion process, it is essential to understand the functioning of a 2-cycle engine. In a 2-cycle engine, the crankcase is a sealed chamber that experiences alternating cycles of pressure and vacuum as the piston moves forward and backward inside the cylinder. As the piston travels forward, a vacuum is created in the crankcase, drawing in the fuel-air mixture from the carburetor. When the piston moves rearward, it creates pressure, forcing the fuel-air mixture out of the crankcase and into the combustion chamber through the transfer ports.
Converting the Fuel Lines and Connectors:
The old dual fuel lines and connectors need to be replaced with a newer single-line setup. Remove the old dual-line quick connector and replace it with a single-line fitting. The OMC part number for this conversion may be obsolete, but aftermarket parts are available, such as the Moeller #033400-10 Johnson/Evinrude Male Fuel Tank Connector, which can be purchased online for a reasonable price.
Modifying the Fuel Pump:
The fuel pump may require modifications to work with the new single-line fuel system. The secret to making the fuel pump functional is to convert the source of pressure for the original pressure tank into a source of pressure and alternating vacuum to operate the fuel pump. The old pressure tank was typically powered by a hose connected to the intake manifold, which had check valves and was located under the carburetor.
By-pass Cover and Adapter Plate:
In some cases, you may need to modify the upper bypass cover to accommodate the new fuel pump. Create an adapter plate using a fuel pump gasket as a template. Drill and tap holes in the adapter plate to mount the fuel pump. Clean the paint off the block area and drill a hole in the center (vacuum hole) for alignment. Epoxy or weld the adapter plate onto the block, ensuring a secure fit.
Re-routing Fuel Lines:
The fuel filter/sediment bowel is not necessary for the new single-line system, but if it is already mounted, you can choose to leave it and re-route the fuel lines accordingly. Ensure that the new fuel line connector is properly positioned, as shown in the provided images.
This conversion process can be applied to most older OMC engines, especially those before 1959, which used a dual-line fuel tank hose without a separate fuel pump. It is important to note that these old dual-line fuel systems are becoming harder to find and can be expensive. Additionally, they were prone to performance issues if there were any leaks in the system.
Copper Tubing for Fuel Line: Safe or Not?
You may want to see also
Explore related products
Using an adapter to convert the OEM fuel feed hard line
The OEM fuel feed hard line can be converted to braided flex line for AN fittings. This process is best done with the engine out, as the space is cramped. The first step is to prep the fuel rail. Most OEM rails have a fuel input "shaft" with a banjo fitting connector and a nut on top, sandwiching the banjo fitting between crush washers. If you have this style, you will need to remove the shaft by unthreading it from the rail. This can be difficult as it is hardened steel and on very tight. You will need to remove the fuel rail from the engine and use a large/strong set of vice grips to get it to turn.
The next step is to slide the tube sleeve and nut up to the flare and thread on to the -5an/-6an reducer to the -5an side. If the tube sleeve is getting stuck near the flare, grab the nut, pull it over the sleeve, and use the nut to force the sleeve up to the flare. Then, connect the -6an end of the reducer to the braided line. Install the EF civic fuel filter and the -6an female to male 90-degree bend on the adaptor. Install the other end of the braided line on the 90-degree bend adaptor.
Finally, install a fuel feed line from the filter to the rail, snug everything down, but do not over-tighten as the alum fittings will strip. Prime the fuel pump three times to bring the system to full pressure and check for leaks.
Fuel Line Retaining Clips: What Are They and Why Are They Important?
You may want to see also
Explore related products
Joining two 3/16 hard fuel lines
Step 1: Understanding Fuel Line Types
Before joining the 3/16 hard fuel lines, it's essential to understand the different types of fuel lines used in vehicles. The two most common types are metal fuel lines and flexible fuel hoses. Metal fuel lines, typically made of steel or aluminum, are known for their durability and corrosion resistance. Flexible fuel hoses, on the other hand, are constructed from rubber or synthetic materials, offering high flexibility and ease of installation.
Step 2: Selecting the Right Fittings
When joining 3/16 hard fuel lines, you have several fitting options to choose from. Compression fittings, widely used in fuel systems, provide leak-free connections and are available at affordable prices, typically ranging from $2 to $10 per fitting. Quick-connect fittings offer convenience and can cost between $5 and $20 or more per connector. Barbed fittings are relatively inexpensive, usually priced between $1 and $5 each. Push-lock fittings are a good choice and generally range from $5 to $15 per fitting. Threaded fittings have a wide price range, starting at around $2 and going up to $10 or more, depending on the design.
Step 3: Preparing the Fuel Lines
Before joining the fuel lines, ensure they are properly prepared. Cut the lines to the required length, making sure they fit securely without any obstructions. If you're connecting metal fuel lines, you may need to flare the ends to create a secure connection.
Step 4: Using Tube Nuts and Unions
To join the 3/16 hard fuel lines, you can use tube nuts and unions. Visit your local hydraulic shop or auto parts store to purchase two tube nuts and an AN(JIC) union to match your fuel line size. Secure the tube nuts onto the fuel lines and then connect the lines using the AN(JIC) union. Ensure that the union is properly tightened to prevent leaks.
Step 5: Alternative Methods
If you prefer an alternative method, you can use a swedging tool to join the fuel lines. Insert one line inside the other and sweat them together, similar to copper water pipes. This method requires a MAP gas torch, Oaty flux, and solder, which can be purchased from hardware stores or home improvement retailers.
Step 6: Safety and Compatibility
Always prioritize safety and compatibility when working with fuel lines. Ensure that the fittings and connections are secure and leak-free. Consider using higher-quality connectors for added durability and reliability, even if they come at a slightly higher price. Additionally, be cautious when working with flammable liquids and gases, and make sure the work area is well-ventilated.
By following these steps and staying committed to safety, you can successfully join two 3/16 hard fuel lines, ensuring a secure and leak-free connection for your vehicle's fuel system.
Fuel Line Size Guide for Toro Walk-Behind Mowers
You may want to see also
Explore related products
Removing the fuel rail
To remove the fuel rail, you will first need to disconnect the fuel lines. Undo the fuel inlet line and the fuel return from the front, using a line wrench to remove the nuts. You may need to remove the alternator to get it out of the way and unscrew any small brackets holding the fuel lines.
Once the fuel lines are disconnected, you will need to unlock the fuel rail from the fuel line. To do this, use a 3/8 socket and wrench to release the clips that secure the injectors. Be sure to also detach the fuel damper and fuel pressure regulator, which are connected to the gas supply line and gas return line, respectively.
With the fuel rail unlocked, you can now detach it from the engine. Use a 3/8-inch ratchet, socket, and extension to carefully lift it out of the engine bay. Be sure to keep an even grip on both sides of the fuel rail to remove it evenly. There are four bolts holding the rail in place, with two bolts nearest the intake manifold that may be difficult to locate as they are below the fuel pressure regulator and damper.
Finally, inspect the O-rings on the fuel rail and replace them if necessary.
Bending Poly Armor Steel Fuel Lines: 3/8 Inch Guide
You may want to see also
Explore related products
![[Apple MFi Certified] 2 Pack Lightning to 3.5 mm Headphone Jack Adapter, iPhone Aux Adapter Converter Dongle Audio Cable Compatible with iPhone 14 13 12 11 X XS 8 7](https://m.media-amazon.com/images/I/51WgdGnCFvL._AC_UY218_.jpg)
Understanding the 2-cycle engine
To understand the 2-cycle engine, it is important to know that it is a type of internal combustion engine. The 2-cycle engine is also known as a two-stroke engine. This type of engine completes a power cycle with two strokes of the piston (one up and one down movement) in a single crankshaft revolution. This is in contrast to a four-stroke engine, which requires twice as many piston strokes and two crankshaft revolutions to complete a power cycle.
The two strokes in a 2-cycle engine refer to the two strokes of the piston through the cylinder, which are the upstroke and the downstroke. During the upstroke, the piston moves from the bottom dead center to the top dead center, completing the exhaust and intake processes. The second stroke, or downstroke, involves the combustion of the mixture, the expansion of the burnt mixture, and the beginning of the scavenging flows near the bottom dead center.
The 2-cycle engine has a sealed crankcase, where alternating cycles of pressure and vacuum occur as the piston moves back and forth inside the cylinder. When the piston moves forward, it creates a vacuum in the crankcase, drawing in the fuel-air mixture from the carburetor. As the piston moves backward, it generates pressure inside the crankcase, forcing the fuel-air mixture out through the transfer ports and into the combustion chamber above the piston.
Two-stroke engines are commonly used in lightweight or portable applications, such as chainsaws and motorcycles, due to their mechanical simplicity, lightweight nature, and high power-to-weight ratio. They are also used in power tools like leaf blowers and glider planes. However, in regions with stringent emissions regulations, two-stroke engines have been phased out in favour of four-stroke engines, which produce lower emissions.
Fuel Line Routing: EFI to Carb Conversion Guide
You may want to see also
Frequently asked questions
A 2-line fuel system is where there are two fuel lines coming off the tank, one is the main fuel line, and the other is the return line back to the tank.
Older 2-line fuel systems are prone to failure if there is a slight leak, causing the motor to not perform or start. Converting to a single-line fuel system can prevent this issue.
The process involves understanding the functioning of a 2-cycle engine and its sealed crankcase, as well as making changes to the fuel pump and fuel lines.
It is best to perform the conversion with the engine out, as space can be cramped. Additionally, it is important to use high-quality fuel lines to ensure safety.
