The size of the fuel line is determined by the outside diameter. Fuel Connector, 3/8" and 5/16" Mercury Marine, Chrysler/Force/US Marine. A blocked outboard fuel line prevents fuel from getting to the motor. Remember that maximum HP occurs at an A/F ratio of 13:1. What is the consensus here on that? Anyone done this? Fuel tanks are available in 25 liter (6.6 U.S. gallon) and 12 liter (3.1 U.S. gallon) sizes, and come standard with the fuel connectors and fuel gauge. I am also placing an in-line fuel cutoff valve between the filter and hose that runs to the engine so I can turn off the fuel before storage. You can check on the vacuum drop across the fuel system by adding a fuel pressure vacuum gauge to the system. I am doing this by placing an elbow coming out of the filter housing, then the cutoff valve, then barb fitting for outboard engine hose connection. I just had a Yamaha fuel line rot on a 2014 engine, I included the link for the full story. From: $5.25 . 99 The key to sufficient fuel supply is pumping power. The pressure drop at 1320 HP thru a 3/8” steel line might be around 5 psi. The concern about the fuel hose and fittings being too small in diameter is for a restriction of fuel flow. Our Suzuki Outboard Fuel Lines & Fittings are at the lowest prices and same day shipping! Yes. This is an interesting article that I came across that seems to be pretty relevant. He gave the AR line a specific name I don't remember. Next back to the fuel cutoff switch; based on the placement of the remote water sep filter housing, I would need to do an elbow out of the filter housing, attach the fuel shutoff valve, then the hose barb to the shutoff valve. Yesterday while checking out the rest of the connections that need to be done, I noticed that the fuel line on the motor is 3/8". Lets assume we have about 10 feet of 3/8” fuel line. We won’t go into why one chooses such rich air fuel ratios; suffice to say that using a BSFC of .5 is generous. Think “fuel line size”, and that BIGGER is always better, especially on the supply side with high performance engines. Sourced from http://www.blowerworks.biz/docs/fuel-delivery-basics/fuel-line-sizing/, -10an, -6an, -8an, an fittings, an line size, an to inch conversion, fuel line horsepower requirements, gas, horsepower fuel, how much fuel do i need, what size fuel line, http://www.blowerworks.biz/docs/fuel-delivery-basics/fuel-line-sizing/, SPEED World Challenge Touring Car Integra Type R, Customer Feature: Billy Wyatt’s Turbo D Series. SG becomes a factor if there is vertical lift of the liquid involved or very long pipe runs (which represent a large physical mass of liquid.) SG simply determines the weight of the liquid per unit volume and it boils down to more weight requires more power (HP) to move it. $8.66 . The pressure drop thru a 3/8”id line at 60 GPH is less than 1 psig! Re: Help with 9.5 hp fuel line size 1964 I don't know about a price difference. Outboard Fuel Lines & Fittings. They don't pull it very well.) Water has relatively high surface tension. Now we are going to calculate the pressure drop thru a 3/8” steel line for a typical vehicle at a flow of 83.3 gph or 1000 HP. Alcohol greatly reduces that tension. (External pumps push fuel. Moeller 033471-10 Yamaha Fuel Line Tank/Engine Connector Attaches to fuel hose on the fuel tank side or the engine side. Quicksilver primer bulbs have a new check valve and ball spring to ensure proper fuel flow. I plan to put a 5/16 to 3/8 barb connector in the line for now. Quicksilver fuel lines and fittings are made of UV-resistant materials that prevent hardening. 89 I am using all 1/4-inch brass fittings. High cylinder temperature leads to problems. For OMC Pressurized Systems. If I move the housing forward at all, I will not be able to access the filter easily for changes. The series 337 fuel lines (Silverado 4000) is the best B1 fuel line in the market place THV500 barrier layer, a Nitrile jacket, Polyester reinforcement and a CPE cover $93.33 - $98.43 Seachoice® Primer Bulb When using E85, alcohol, methanol, etc. 5 In Stock - Ships Immediately. Since 1968, West Marine has grown to over 250 local stores, with knowledgeable Associates happy to assist. Competitor primer bulbs have an inferior check valve that can stick when it’s closed. The fuel line, along with the other parts of a fuel system, are responsible for delivering the fuel from the fuel cell into the carburetor. Completing the measurement is simple and takes relatively few tools. The NAPA dealer I first went to did not have the AR line in stock. It generally starts with a partial blockage, where playing around with the fuel hose and pumping the primer bulb will get the motor to start or keep it running. 1000 divided by 12 = 83.3 Gallons Per Hour or 315 Liters Per Hour. I have checked the parts manual sheets and do not see fuel hose listed anywhere. If you plan to replace existing hoses and fittings, I would use 3/8-inch ID hose and appropriate fittings, rather than use 5/16-inch. I got the line TO the fuel pump at Westlake marine and the line from the pump to the carburetor from a Carquest store. Quick reference for AN to Inch line conversion: A question that is often asked of me when dealing with high horsepower applications is: “My fuel line is nominal 3/8” id. The reason most people do not understand why is because “back in the day” when carburetors ruled and everybody ran a Holly electric fuel pump running at 14 psig then into a rail mounted PRV set to 6 psig the “pump head” was insufficient to overcome the pressure drop thru the 3/8” line: particularly if the pump was at the front of the vehicle. Ingersoll-Rand publishes an engineers’ handbook called “Cameron Hydraulic Data”. Your order may be eligible for Ship to Home, and shipping is free on all online orders of $35.00+. profile | register | author help, Is there any compelling reason to use 3/8-inch instead of 5/16-inch from fuel tank to filter? One bit of advice, try not to run the motor dry before switching tanks. The 25 can use either size line without a problem. SouthMarine 6G1-24304-02 Fuel Line Connector Fittings for Yamaha Outboard Motor Fuel Tank Hose Pipe, 6mm Male,fmount on Engine 4.3 out of 5 stars 35 $12.89 $ 12 . Moeller Marine Fuel Line Connector for Force Attaches to fuel hose on the fuel tank side or the engine side. If a cylinder runs lean, the cylinder temperature will be higher. As another example let’s look at a flow of 1 gallon per minute at a required fuel rail pressure of 70 psig. Sort & Filter . © Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000. Place a small drop of water on a counter top. Click here to view dimensions of tank. Low surface tension and/or low viscosity liquids overcome that resistance more easily. Shop with confidence - get free shipping to home or stores + price match guarantee! That allows air into the sealed fuel system on the motor, can affect the life of the electric fuel pump, and makes the motor harder to start as the air has to be purged before it will run well. Watch the water immediately spread out on the counter top. Fuel Line Assembly, 3/8" Rubber Braided Marine Outboard Boat Motor RVs Fuel Hose Line Assembly with Primer Bulb Steel Hose Clamps 6FTFuel Assembly with Primer Bulb Steel Hose Clamps 6FT (3/8"-Rubber) 4.3 out of 5 stars 73 $15.99$15.99 Get it as soon as Thu, Oct 1 The 5/16 feed the 85 hp Force with no problems. The reason I am making all these conversions for you is because typical fuel pump measurements are made in volume versus mass although mass is more accurate. Shop with confidence - get free shipping to home or stores + price match guarantee! Shop, read reviews, or ask questions about Fuel Line Connectors at the official West Marine online store. The key factors are viscosity and surface tension of the liquid being pumped. Find FUEL LINE 5/16"ID - 0772564 here. If we use alcohol we need about double the flow or with E85 we need to increase the flow numbers by around 30 % . BTW, this is an area of misunderstanding with people. Don’t I need to increase the size of the fuel line to at least ½” id (from a #6 to a #8 or #10) to support say 600 HP”? Offering discount prices on OEM Johnson/Evinrude, OMC parts for over 50 years. Will increasing the line size to ½” help? Friction loss is the mechanical resistance exercised by the pipe wall on the liquid. A 3/8”id fuel line can easily support 600 HP given sufficient “pump head”! Since 1968, West Marine has grown to over 250 local stores, with knowledgeable Associates happy to assist. If I use 20 feet of steel pipe then that is 1/5 of 15 or 3 psi using water (gasoline is less viscous and flows more freely). Sierra 18-8051 Double Fuel Line Assembly for Johnson, Evinrude Sierra 18-8051 is a replacement fuel line assembly for use with OMC, Johnson, and Evinrude engines. Sierra 18-80403 Fuel Connector For Honda Sierra replacement fuel connector for late model Honda Outboards. Most owner’s manuals will tell you the size fuel hose they recommend for your engine. Will increasing the line size to ½” help? Using the pressure drop thru a new steel pipe of .364” id at 1.388 gpm (83.3 gph) we get a head loss of 35 feet per 100 feet of pipe with water as the medium. The ½” line will result in a ½ pound drop versus the 3 pound drop for the 3/8” line at the stated flow of 83.3 gph (enough to support 1000 HP at a BSFC of .5). Consider that most greases have a lower SG than water but much higher viscosity. (The counter top is analogous to the pipe wall) The water lies on the counter as a small bubble. 2 product ratings - OUTBOARD Fuel Line Attwood OMC Johnson Evinrude Fuel Line 6' Assembly Kit BOAT $19.99 Trending at $27.50 Trending price is based on prices over last 90 days. Yes the pressure drop thru a ½” line is a nominal 5 feet versus 35 feet for the 3/8” id fuel line. Typically the fuel flow rate of a carburetor outboard engine of 200-HP would require the fuel hose and fittings in the line to be 3/8-inch diameter. Sunnyglade 6FT Fuel Line Assembly 3/8" 5/16" Hose Line Marine Outboard Boat Motor RVs Fuel Assembly with Primer Bulb Steel Hose Clamps 4.0 out of 5 stars 136 $14.99$14.99 FREE Shipping on your first order shipped by Amazon It is important to have the right size so the vehicle operates efficiently. Gasoline has lower viscosity and much lower surface tension than water, which is why it flows more easily thru a pipe. Mfr: Sierra / Seastar Solutions. 5/16" Barb Female fuel line tank or engine connector. Don’t touch the water but let a very small drop of alcohol drip into the water. However, given sufficient pumping power, a one (1) pound drop versus a tenth (1/10) pound drop is insignificant. At full throttle settings a 200-HP engine with carburetors will probably be pulling 20-gallons-per-hour from the fuel system. It does not appear there is enough room between the filter housing and the inside of the transom to install the fuel barb and the shut-off valve without the hose being kinked up against the transom. At 500 HP the pressure drop is even less. We recommend you install a 100 Micron In-Line Fuel Filter between the tank and the pump. Powered by: Ultimate Bulletin Board, Freeware Version 2000Purchase our Licensed Version- which adds many more features! Boat Motor Fuel Line Hose with connector and Primer Assy 6Y2-24306-55-00 6Y2-24306-56-00 for Yamaha Outboard Motors, 6mm/1/4in Pipe, 3m length 4.4 out of 5 stars 108 $33.89 $ 33 . That is enough fuel to support 720 HP. Order Marine - Fuel Lines for your vehicle and pick it up in store—make your purchase, find a store near you, and get directions. Which do you think flows more easily thru a pipe? Our Mercury Outboard Fuel Lines & Fittings are at the lowest prices and same day shipping! At WOT (Wide Open Throttle) a BSFC (Brake Specific Fuel Consumption) of ½ pound of fuel per horsepower is quite safe: resulting in A/F ratios of 11:1 or richer. Mercury - Mariner Outboard Fuel Line Assemblies and Parts. 89 The fuel line from the gas tank is 5/16". If you put a drop of gasoline or alcohol (low surface tension liquids) on the counter top you see they immediately spread out. Let’s see why today this is what I call a “wives’ tale”. Yes. FREE Shipping Usually ships within 6 to 10 days. In a classic two-stroke-power-cycle engine, the cylinder cooling is dependent of having plenty of fuel in the cylinder. Let’s double that to say 20 feet to take care of the bends in the steel pipe from the gasoline tank up to the engine fuel rail. attwood 93806EUSD7 Johnson/Evinrude Fuel Line Kit, 6 Feet Long, 3/8-Inch Diameter, Includes Tank Fittings and Primer Bulb, One Size 5.0 out of 5 stars 10 2.31 feet of water = 1 psi therefore 35/2.31 = 15 psi per 100 feet. Since 1968, West Marine has grown to over 250 local stores, with knowledgeable Associates happy to assist. Narrow By . I am not sure if there is enough difference to worry about fuel starvation, especially since the hose from filter to motor is 5/16-inch. Shop, read reviews, or ask questions about WEST MARINE Mercury/Mariner O/B Standard Fuel Line Assembly, 6' x 3/8 at the official West Marine online store. 90 There is usually a specification for an outboard engine for the most vacuum in the fuel system, typically being limited to about 4-PSI negative pressure. For this example I will use gasoline. Given a big enough pump a 3/8” steel line could support 1000 HP. 17 Products . Shop Suzuki Outboard Fuel Lines & Fittings at Wholesale Marine. Yes the pressure drop thru a ½” line is a nominal 5 feet versus 35 feet for the 3/8” id fuel line. In there they list the “Friction Of Water” thru various types of pipe. The answer is “NO”! Ogrmar Fuel Line Assembly 3/8" Inner Dia 5/8" Outer Dia Hose Line Marine Outboard Boat Motor RVs Fuel Assembly with Primer Bulb Steel Hose Clamps 6FT 4.4 out of 5 stars 1,282 $15.99 $ 15 . Here is a little experiment you can try. Thanks Jason. Fix of a Yamaha no start, hard start, caused by bad fuel connector and bad hose. The simple way to know is to install an electronic fuel pressure gage. Check here for special coupons and promotions. search | FAQ | Most of you know that the pressure drop thru a straight pipe is less than an elbow or a 45 (same principle as your air ducting from your blower thru the piping and on into the engine). OK stay with me now as we calculate how much gasoline fuel we need to support say 1000 HP. 99 List List Price $27.90 $ 27 . Lots of strange information out on the internet regarding fuel line sizing and it seems like most of the time people run way more diameter fuel line than they need. Can I tolerate a 3 psig drop if I need the fuel delivered at 60 psig? ... Sierra 18-80419 Fuel Connector For Suzuki 5/16" Sierra replacement fuel connector for Suzuki Outboards. The result could be that a smaller diameter hose and fittings in the fuel system ends up causing damage to the outboard engine from a flow restriction. The ½” line will result in a ½ pound drop versus the 3 pound drop for the 3/8” line at the stated flow of 83.3 gph (enough to support 1000 HP at a BSFC of .5). Listed anywhere, I would use 3/8-inch id hose and appropriate fittings, I included the link for the story. An electronic fuel pressure vacuum gauge to the system seems to be pretty relevant ’... A very small drop of alcohol drip into the water immediately spread out on the wall! Diameter is for a restriction of fuel flow valve that can stick when it ’ s manuals tell! Hp fuel line Tank/Engine connector Attaches to fuel hose on the fuel Assemblies... 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