outboard fuel line size

I replaced all the stock Yamaha lines on the high pressure side with fuel injection line 5/16, which seems to be almost the exact diameter. Shop Mercury Outboard Fuel Lines & Fittings at Wholesale Marine. profile | register | author help, Is there any compelling reason to use 3/8-inch instead of 5/16-inch from fuel tank to filter? Re: Help with 9.5 hp fuel line size 1964 I don't know about a price difference. 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. 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. Shop with confidence - get free shipping to home or stores + price match guarantee! 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. 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. For OMC Pressurized Systems. 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 pressure drop at 1320 HP thru a 3/8” steel line might be around 5 psi. But before you do check out the following (and remember a dirty fuel filter is often the culprit of falling fuel pressures!). Lets assume we have about 10 feet of 3/8” fuel line. Shop, read reviews, or ask questions about Fuel Lines at the official West Marine online store. The simple way to know is to install an electronic fuel pressure gage. In a classic two-stroke-power-cycle engine, the cylinder cooling is dependent of having plenty of fuel in the cylinder. Yes the pressure drop thru a ½” line is a nominal 5 feet versus 35 feet for the 3/8” id fuel line. The pressure drop thru a 3/8”id line at 60 GPH is less than 1 psig! VISCOSITY SG plays no role in friction loss. Shop, read reviews, or ask questions about Fuel Line Connectors at the official West Marine online store. Features rectangular locking post. 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. If I move the housing forward at all, I will not be able to access the filter easily for changes. The answer is “NO”! 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 Quicksilver primer bulbs have a new check valve and ball spring to ensure proper fuel flow. (The counter top is analogous to the pipe wall) The water lies on the counter as a small bubble. 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). He gave the AR line a specific name I don't remember. High cylinder temperature leads to problems. 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. 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). Ingersoll-Rand publishes an engineers’ handbook called “Cameron Hydraulic Data”. Remember that maximum HP occurs at an A/F ratio of 13:1. 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. 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. Moeller Marine Fuel Line Connector for Force Attaches to fuel hose on the fuel tank side or the engine side. I have checked the parts manual sheets and do not see fuel hose listed anywhere. The 25 can use either size line without a problem. Place a small drop of water on a counter top. Shop with confidence - get free shipping to home or stores + price match guarantee! 89 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. Remote FF housing housing is located on the starboard wall of the bilge, just under the access hatch. Product Title Fuel Line Hose Outboard Primer Bulb fit Yamaha 6Y2-24306-56-00(Check for more model#) Average Rating: ( 1.0 ) out of 5 stars 3 ratings , based on 3 reviews Current Price $21.99 $ 21 . 5 In Stock - Ships Immediately. Narrow By . Click here to view dimensions of tank. Here is a little experiment you can try. If the pressure falls as the engine RPM’s go up you need more pump head. search | FAQ | 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). Anyone done this? A 3/8”id fuel line can easily support 600 HP given sufficient “pump head”! Order Marine - Fuel Lines for your vehicle and pick it up in store—make your purchase, find a store near you, and get directions. Offering discount prices on OEM Johnson/Evinrude, OMC parts for over 50 years. Outboard Fuel Lines & Fittings. 1000 divided by 12 = 83.3 Gallons Per Hour or 315 Liters Per Hour. Our Mercury Outboard Fuel Lines & Fittings are at the lowest prices and same day shipping! Our Suzuki Outboard Fuel Lines & Fittings are at the lowest prices and same day shipping! Sort & Filter . Low surface tension and/or low viscosity liquids overcome that resistance more easily. 17 Products . Mercury - Mariner Outboard Fuel Line Assemblies and Parts. go up to the next bigger fuel line. For this example I will use gasoline. We won’t go into why one chooses such rich air fuel ratios; suffice to say that using a BSFC of .5 is generous. That is enough fuel to support 720 HP. BTW, this is an area of misunderstanding with people. A Fuelab Model 41401 can deliver 90 gph @ 70 psig. 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". Since gasoline has a weight of 5.994 lbs/gallon (@ a SG of .7201 typical) then in round numbers we need 1 gallon of gasoline per 12 HP (5.994/.5). 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 . 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. The NAPA dealer I first went to did not have the AR line in stock. 90 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”? Sierra 18-80403 Fuel Connector For Honda Sierra replacement fuel connector for late model Honda Outboards. The key factors are viscosity and surface tension of the liquid being pumped. 5/16" Barb Female fuel line tank or engine connector. 99 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. Mfr: Sierra / Seastar Solutions. I got the line TO the fuel pump at Westlake marine and the line from the pump to the carburetor from a Carquest store. Most owner’s manuals will tell you the size fuel hose they recommend for your engine. Can I tolerate a 3 psig drop if I need the fuel delivered at 60 psig? I am using all 1/4-inch brass fittings. Yes. 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 . Which do you think flows more easily thru a pipe? Watch the water immediately spread out on the counter top. In there they list the “Friction Of Water” thru various types of pipe. 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. Switching to a ½” id line would result in a pressure of about 1/10 of the 3/8” line. 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). Your order may be eligible for Ship to Home, and shipping is free on all online orders of $35.00+. 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. 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. Shop with confidence - get free shipping to home or stores + price match guarantee! 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. Will increasing the line size to ½” help? 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. What is the consensus here on that? If you put a drop of gasoline or alcohol (low surface tension liquids) on the counter top you see they immediately spread out. Ogrmar Fuel Line Assembly 3/8" Inner Dia 5/8" Outer Dia Hose Line Marine Outboard Boat Motor RVs … The concern about the fuel hose and fittings being too small in diameter is for a restriction of fuel flow. Since 1968, West Marine has grown to over 250 local stores, with knowledgeable Associates happy to assist. 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. © Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000. ... Sierra 18-80419 Fuel Connector For Suzuki 5/16" Sierra replacement fuel connector for Suzuki Outboards. Let’s see why today this is what I call a “wives’ tale”. Since 1968, West Marine has grown to over 250 local stores, with knowledgeable Associates happy to assist. Yes the pressure drop thru a ½” line is a nominal 5 feet versus 35 feet for the 3/8” id fuel line. The fuel line after the pump can be the next smaller size. Quicksilver fuel lines and fittings are made of UV-resistant materials that prevent hardening. One bit of advice, try not to run the motor dry before switching tanks. Powered by: Ultimate Bulletin Board, Freeware Version 2000Purchase our Licensed Version- which adds many more features! 2.31 feet of water = 1 psi therefore 35/2.31 = 15 psi per 100 feet. 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 . Moeller 033471-10 Yamaha Fuel Line Tank/Engine Connector Attaches to fuel hose on the fuel tank side or the engine side. 89 Fix of a Yamaha no start, hard start, caused by bad fuel connector and bad hose. Gasoline has lower viscosity and much lower surface tension than water, which is why it flows more easily thru a pipe. 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.) 99 List List Price $27.90 $ 27 . From: $5.25 . I plan to put a 5/16 to 3/8 barb connector in the line for now. Check here for special coupons and promotions. This is an interesting article that I came across that seems to be pretty relevant. A blocked outboard fuel line prevents fuel from getting to the motor. 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. If we use alcohol we need about double the flow or with E85 we need to increase the flow numbers by around 30 % . Yes. 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 OK stay with me now as we calculate how much gasoline fuel we need to support say 1000 HP. Fuel Connector, 3/8" and 5/16" Mercury Marine, Chrysler/Force/US Marine. $8.66 . Shop Suzuki Outboard Fuel Lines & Fittings at Wholesale Marine. The key to sufficient fuel supply is pumping power. When using E85, alcohol, methanol, etc. 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. If a cylinder runs lean, the cylinder temperature will be higher. Given a big enough pump a 3/8” steel line could support 1000 HP. Think “fuel line size”, and that BIGGER is always better, especially on the supply side with high performance engines. The alcohol broke down the surface tension and the water molecules were free to move. Competitor primer bulbs have an inferior check valve that can stick when it’s closed. You can check on the vacuum drop across the fuel system by adding a fuel pressure vacuum gauge to the system. Consider that most greases have a lower SG than water but much higher viscosity. The size of the fuel line is determined by the outside diameter. FREE Shipping Usually ships within 6 to 10 days. This ensures gravity feeds fuel to the pump. 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. However, given sufficient pumping power, a one (1) pound drop versus a tenth (1/10) pound drop is insignificant. More pump head can be achieved with a bigger pump, higher pump voltage and/or increasing the line size. 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. I just had a Yamaha fuel line rot on a 2014 engine, I included the link for the full story. 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. The fuel line from the gas tank is 5/16". Since 1968, West Marine has grown to over 250 local stores, with knowledgeable Associates happy to assist. The 5/16 feed the 85 hp Force with no problems. Alcohol greatly reduces that tension. Friction loss is the mechanical resistance exercised by the pipe wall on the liquid. We recommend you install a 100 Micron In-Line Fuel Filter between the tank and the pump. At full throttle settings a 200-HP engine with carburetors will probably be pulling 20-gallons-per-hour from the fuel system. Will increasing the line size to ½” help? Don’t touch the water but let a very small drop of alcohol drip into the water. Water has relatively high surface tension. (External pumps push fuel. Completing the measurement is simple and takes relatively few tools. They don't pull it very well.) It is important to have the right size so the vehicle operates efficiently. 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. 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. Thanks Jason. Find FUEL LINE 5/16"ID - 0772564 here. 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 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 doing this by placing an elbow coming out of the filter housing, then the cutoff valve, then barb fitting for outboard engine hose connection. At 500 HP the pressure drop is even less. I have read in some places that 90 degree elbows are a no-no in fuel lines. As another example let’s look at a flow of 1 gallon per minute at a required fuel rail pressure of 70 psig. Flows more easily thru a pipe fuel Lines and fittings being too in! You install a 100 Micron In-Line fuel Filter between the tank and the pump to the carburetor from Carquest... 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At 60 gph is less than 1 psig + price match guarantee will increasing the line to fuel...