Symptoms of a bad fuel water separator. The oil separator removes the oil from the crate case vapors and feeds it back into the system by channeling the blow-by gases through a series of baffles or filters. I clamped up the only hose that seemed to have a vacuum issue. Replace all fuel filters during preventive maintenance, bleed the system to remove air, and check for cracked hoses or A fuel water separator is part of this fuel system that prevents the water from getting into the fuel tank. During those two weeks I found this thread where two people described similar symptoms and fixed the problem by replacing the high-pressure (in-line) fuel filter - between the Vapor Separator and the high-pressure fuel pump. When you're out on the water, few things are more frustrating than engine problems disrupting your day. These are the main causes of a bad fuel pump. It could be watery fuel. Also, check for anti-siphon valve proper operation (usually in tank outlet) and for debris blocking the tank pickup screen. 7 roughly 140,000 miles, my water in fuel light came on drain separator. Discover the common bad oil separator symptoms to prevent engine damage and costly repairs. Stay informed and keep your vehicle running smoothly with our expert tips. Ethanol problems combined with normal condensation -- and sometimes a bad load of fuel -- mean that your boat needs good water separators in place. Do you know why your fuel water separator is so important? It keeps your engine running longer, prevents engine damage (especially to your fuel injectors), and it's an expensive part to replace. A water seperator is a filter and you change it once a year or once it gets a certain amount of water in it and it doesn't flow fuel as well as it used to. Drain off about 1/4 cup every 3-4 fill ups and look for water in the fuel In this video I cover fuel system maintenance, including inspecting the fuel grommet, cleaning the water separator, checking the fuel lines, replacing the fuel filter, and bleeding the fuel system. It can be in the tank from the fuel delivery truck and from the actual gas station or marina. Did you know gasoline has a shelf life? Learn what makes gas bad, 8 symptoms of bad gas in a car to look for and improve vehicle functionality. It is typically installed on diesel engines, but can also be used on gasoline engines. The wrench light comes on when the water separator light comes on. Get a water separator sensor, take the fuel filter out and spray b-12 through the sensor hole and clean best as possible. Had this last year and it turned out to be the fuel pump. Re: Symptoms of bad water seperator? Not sure exactly what you want to know. 3L V6. This may be due to sedimate build up in the water reservoir or a computer Red River Team, a top pressure vessel manufacturer, ensures excellence in every product. Although the modern purpose of a positive crankcase ventilation (PCV) system is to reduce air pollution, the original purpose was to allow an engine to operate underwater without the water leaking in. I have heard of several folks, including bmzero on this forum, who went through the expense of changing out all their injectors, only to find that the check valve was bad. No Yes, supplement just says it indicated filter is partially filled with water. Still, the process is as simple as removing both filters and priming the water separator filter with fuel before screwing it on. Here are some symptoms of a clogged outboard fuel filter. 0 Water In Fuel Lamp Illuminated: Some trucks may exhibit a water in fuel lamp that continues to illuminate after draining the water separator, or a flickering water in fuel lamp. Find out when to replace it and how much it costs. When an oil separator goes bad, it can lead to a range of issues that can have significant consequences. Get superior quality vessels with our expertise. Most diesel-powered vehicles and equipment have a water separator in the fuel system. Replaced the low pressure fuel filter and also inspected internal fuel/water separator and found no water. I then replaced the plug at the sensor since I read that water can sometimes get into the plug and cause a false water detection. Due to fuel starvation, there is an insufficient flow of fuel which leads to a faulty fuel pump. Here's a quick look at water separating fuel filters, or, water separating gas filters, why you need one, how often it should be replaced, and what to look for when replacing it. The most common 6. Signs of a Bad Fuel Filter Fuel filters can get clogged by anything from algae to sludge to debris in the water. I recently had a no start issue that I believe I may have solved by replacement of the fuel water separator. You are being redirected to the new and improved Fleetguard. Re: What are symptoms of 'full' water separating fuel filter? I've never had it happen with mine, but I would assume if enough water was trapped in the filter, it would "overflow" and water would begin to enter the fuel system, causing poor performance and probably stalling. would often turn into "reduced engine power". Excessive smoke, a burning oil smell, and increased oil consumption are symptoms of a bad vent oil separator. Identify warning signs early to prevent engine stalling and costly repairs on your GMC vehicle. Any reason you aren't just changing it? theSkimm makes it easier to live smarter. I still think that a water separator filter DOES remove water or why would everyone that uses one get around the same mileage between changes? They all get fuel from all different methods and have similar filter change results. Understanding the warning indicators of an air-oil separator malfunction might assist you in resolving issues before they become serious. When was the last time the filter was changed? When water infiltrates your fuel system, it typically gets caught in the fuel filter, which is designed to separate water from fuel. Comprehensive Guide to the 13 most common 6. Water gets into the tank through a variety of different ways. I am thinking bad sensor and am wondering where it might be located and if it can be replaced? What "Bad Gas" Means Getting "bad gasoline" in your outboard can mean two different things. Hey guys, I have 2006 twin 350 Mag Horizon closed cooled (OW360139). Water in diesel is seriously bad news - it can cause corrosion, poor lubrication, and eventually lead to complete system failure requiring costly overhauls. As with conventional fuel filters, you should perform the procedure safely with a container available to catch spilled fuel or residue. Found it: 2003-2005 6. The first PCV systems were built during World War II, to allow tank engines to operate during deep fording operations, where the normal draught tube ventilator would have allowed water to enter Learn about overall engine reliability and problems with Ford's 7. to/3514D3U In this video I go over the process I took to change out the fuel water separator on my 1996 Sea Ray with a Mercruiser 4. Can also be a bad fuel pickup. Your gas cap could need a new o-ring and it's allowing water to seep past. I drained the fuel water separator several times. A fuel water separator is a device that is used to remove water and other contaminants from the fuel in a vehicle's fuel system. It's essential to locate the source of the leak at the fuel water separator to determine if it can be repaired or if the entire assembly needs replacement. These all can happen due to a clogged VST filter. Discover how to identify, prevent, and treat water in fuel to maintain engine performance and efficiency. com Diesel filter water separator The solution is a diesel filter water separator (see diagram). In this article, we'll explore what happens when an oil separator malfunctions and the Even just a single bad injector running at 150% output, can overwhelm your DPF/DOC emmissions system with unburned fuel and result in frequent regens and potentially leading to a plugged DPF and frequent cleanings. 3 filter/water separator can develop fuel/air leaks at the fuel heater and restriced filter sensor or the filter drain (all three are servicable) and water in fuel sensor o-ring. All these issues can be avoided if you take swift action based on the symptoms. Cost to Replace and Repair Mercury Outboard Faulty Fuel Pump This segment would give you an idea about the cost of replacing and repairing the Mercury fuel pump. Amazon link for filter: https://amzn. Air entering the system can cause engine shutdown; ensure all filter elements are properly seated and tightened. 3 Powerstroke diesel engines, including numerous sensor and valve issues. 4L Powerstroke problems are What happens when an oil separator goes bad? An oil separator is a critical component in various industrial and automotive systems, responsible for removing oil and other contaminants from the airflow. As water is denser than fuel, it collects at the bottom of the filter, making it easy to remove. Fuel water separators are an important component of any marine fuel system. First check your gas tank, water separator, lines and vents. Whether you own a Yamaha, Mercury, Johnson, or any other outboard brand, understanding the symptoms of fuel pump problems can save y I have a 2013 6. Apr 25, 2006 · Re: What are symptoms of 'full' water separating fuel filter? I've never had it happen with mine, but I would assume if enough water was trapped in the filter, it would "overflow" and water would begin to enter the fuel system, causing poor performance and probably stalling. The engine would not start 5 minutes after it was already running but has started both times since. This article explains a step-by-step process of changing a fuel-water separator filter on an outboard. This separator element eliminates that risk by catching the water while letting clean fuel through to your engine. Just curious. Join the millions who wake up with us every morning. What Is The VST On A Yamaha Outboard? On all fuel injected and direct injected Yamaha Outboards. There could be condensation forming in your tank from weather changes. It’s even worse if you’re out in open waters. After a specific time of water trapping, your fuel-water separator will be full or show signs of deterioration due to the accumulation of water, debris, etc. Water contamination in your fuel system can lead to rust, corrosion, and costly repairs - and typically isn’t covered under a standard warranty. Very easy to check all the way back to the tank. 4L Powerstroke problems and how to fix them. Jul 23, 2022 · What are the Symptoms of A Bad Fuel Water Separator? Basic symptoms of a bad fuel water separator are low engine power, stuttering, poor acceleration, and a few others that we’ll now discuss in detail. While the water separator needs priming, the AirDog® fuel filter does not. What is a Fuel Water Separator? Water separating fuel filters are mechanical devices installed in a boat’s motor to act as an added layer of defense for its fuel system. Replacement oil separators can cost anywhere from $10 to $1,800. If the fuel separator is leaking, it can lead to a loss of prime in the fuel system, ultimately causing fuel starvation to the fuel pump and engine. The tech is correct, the fuel/water separator does not need to be changed until it shows fuel near the top of the bowl. There is a component called a Vapor Separator Tank or VST for short. The typical symptoms include misfiring, increased fuel burning, zero pick-ups at higher RPM, and complete power loss. That's why Power Stroke fuel filter maintenance and regular service of your diesel fuel water separator are so important for keeping your engine running well for longer. Have not run external fuel tank to see if it is coming from the fuel tank or the engine because the boat only stalls during load in the water. White smoke from exhaust system Damaged fuel injectors and pumps Testing for Water in Your Diesel Fuel and Tank Expensive diesel repairs due to water in the system is a common problem, it’s a requirement to keep an eye on the quality of fuel in your tank. Take a look. . Feb 12, 2026 · Hard starting after winter? Water in diesel ruins engines. Thanks to the new flash, nothing major. if it stays on, which mine doesn’t, then it means water in tank too (more serious). It contains a filter with hydrophobic characteristics, so that water can’t pass through, and a tap to drain water. To avoid the consequences, you must look for symptoms. Among the most common culprits behind outboard motor issues is a failing fuel pump. Your water separator is back by the tank to the driverside of driveshaftalmost above rear axel. I then replaced the filter, cover and sensor assembly. Learn how to check symptoms and drain your Fuel Water Separator today. It's recommended to replace the head gasket every four years or sooner if usage exceeds typical levels. The goal of a primary fuel filter is to keep contaminants out of your machinery. Your engine could fail for a number of reasons, one of which being your spin-on fuel filter failing. Learn to recognize GMC fuel pump failure symptoms with this guide. Still same issue. I wouldn't suggest air hose! But this is what we do at the dealership!! The 7. The air bleed Schrader valve can leak on either filter. I got it home, and changed the fuel separator and engine oil/filter. When trash or water gets into the fuel supply, it can clog the system or at least cause it to run improperly. Inspect the separator’s drain valve and O-rings for damage. Learn about the symptoms, effects, and preventive measures for water contamination in diesel fuel. No water in the fuel separator. Recognizing the symptoms of water in your fuel filter early can help prevent expensive repairs and keep your vehicle running smoothly. No change. Learn how to identify signs like oil leaks, smoke, and reduced performance early. Symptoms of a Bad or Failing Vent Oil Separator Common signs include smoke coming from the exhaust pipe, the Check Engine Light coming on, excessive oil consumption, and sludge under the oil cap. I ran it for a while, light did not go off Replaced the fuel bulb with a brand new johnson bulb. I did drain that two different times, fuel looked good and no water. Furthermore, a diesel fuel water separator will separate water from the fuel entering your engine. I want to make sure its the little yellow turn knob on the fuel filter housing first of all. Learn how to Identify Honda Fuel Pump Failure Symptoms, what signs to watch for, and when to seek service to keep your Honda running smoothly year-round. I think you have worked hard and are doing right in evaluating potential problems at the fuel end of the system. Signs of a bad fuel pump include the engine bogging down during acceleration or at idle, inconsistent performance, and starting difficulties. Fuel loss at the fuel water separator usually indicates a faulty seal or cracked bowl causing leaks. Have seen it before. Credit: Thanks all members of Audizine and contributors on the net! Since we will be removing a fuel line and TFSI engine operates under a very high fuel pressure, begin with relieving the fuel pressure by pulling fuel pump fuse (it is in the driver’s side fuse block), then start the car and let it run until it dies. Learn what a PCV valve is, how it works, where it's located, and the symptoms of a bad or clogged PCV valve. Yamaha F115 Fuel Pump Issues A common problem with the Yamaha F115 is a malfunctioning fuel pump. A less common problem is a cracked tank pickup tube. My question is This critical piece of equipment can mean the difference between a good and bad day on the water. May 31, 2025 · When water infiltrates your fuel system, it typically gets caught in the fuel filter, which is designed to separate water from fuel. Never did I see any noticable water in the fuel. Re: Bad Vapor Separator?? An air leak anywhere on the suction side of the fuel pump will cause problems. Dec 16, 2025 · Understanding when to replace a fuel water separator—and how to recognize signs of saturation— can help prevent unexpected downtime, expensive repairs, and long-term engine damage. I’ve drained filter 3 times, finally replaced with a new one, same symptoms. They keep water from entering the fuel and damaging your boat. And really on pretty much any brand outboard that has fuel injection. And then I swapped out all three of the sensors on the left side of the throttle body with the sensors from the good twin engine. You may have put gas into the fuel tank that is tainted, or it may actually go bad inside the motor. Though some will call it by other names, like a Mercury’s Fuel Supply Module, or FSM for short. hrwxej, m3ujy, jfrz6, h3znor, ptc2, simj, pzxcc, boqjr, ld5ic, oaihzb,