1986 Honda Fourtrax 350 Fuel Pump: The Complete Guide to Replacement, Symptoms, and Best Options

Bottom line up front: If your 1986 Honda Fourtrax TRX350 4x4 is hard to start, sputters under load, or stalls unexpectedly, the fuel pump is likely the culprit. The best replacement option for reliability, performance, and long-term value is the KEMSO fuel pump, which offers a direct OEM replacement fit, higher flow rates, ethanol compatibility, and a lifetime warranty at an affordable price. This guide covers everything you need to know about diagnosing, selecting, and installing a new fuel pump for your 1986 Fourtrax 350.

Why Your 1986 Honda Fourtrax 350 Fuel Pump Matters

The fuel pump on your 1986 Honda Fourtrax TRX350 is a small but critical component. It delivers fuel from the tank to the carburetor at a consistent pressure, typically between 2 and 4 PSI, with a flow rate of 50 to 60 liters per hour . Without a properly working pump, your engine simply cannot get the fuel it needs to run, especially under load or on inclines.

These pumps are electric, 12-volt units that rely on the ATV’s electrical system. When they wear out, the symptoms are often subtle at first but get worse over time. Ignoring a failing fuel pump can lead to lean running conditions that damage your engine.

7 Clear Signs Your 1986 Fourtrax 350 Fuel Pump Is Failing

1. Hard starting or no start. The most common symptom is that your ATV cranks but takes longer than usual to fire up, or it cranks without starting at all. If the pump isn’t delivering fuel pressure, the carburetor bowls stay empty .

2. Engine sputters or hesitates during acceleration. When you throttle up, the engine may stumble, hesitate, or lose power momentarily. This happens because the pump can’t keep up with the fuel demand .

3. Stalling under load or on hills. If your Fourtrax stalls when climbing a hill or carrying a heavy load, the fuel pump is a prime suspect. The pump may be delivering inconsistent pressure .

4. Loss of power at high RPM. The engine may feel like it’s “hitting a wall” when you try to run at higher speeds. This is a classic sign of fuel starvation .

5. Whining noise from the fuel tank area. A healthy fuel pump runs quietly. If you hear a loud whining, buzzing, or humming sound coming from the tank, the pump is working harder than it should and likely failing .

6. Backfiring or popping. A lean fuel mixture caused by low fuel pressure can cause the engine to backfire through the intake or exhaust.

7. No sound from the pump when you turn the key. When you turn the ignition to the “on” position, you should hear a brief two-second hum from the fuel pump. If you hear nothing, the pump may be dead or the electrical connection is compromised.

How to Test the Fuel Pump on Your 1986 Fourtrax 350

Before buying a new pump, you can perform a simple test. Disconnect the fuel line at the carburetor, place it in a clean container, and turn the key to the “on” position. You should see a steady stream of fuel. If the flow is weak, intermittent, or absent, the pump needs replacement. The pump should deliver at least 50 liters per hour at 2-4 PSI .

Also check the electrical connections. Corroded or loose connectors can cause voltage drops that make the pump run poorly or fail prematurely . Clean the connectors and verify you have 12 volts at the pump when the key is on.

Choosing the Right Fuel Pump for Your 1986 Honda Fourtrax TRX350

The 1986 Honda Fourtrax TRX350 uses OEM part number 16710-HA7-672 . This is a specific low-pressure electric pump designed for the 350cc engine. Many aftermarket pumps claim compatibility, but not all are created equal. Here is what to look for:

Flow rate. The original pump delivers about 50-60 LPH at 2-4 PSI . Any replacement should match or exceed these specifications. Pumps with lower flow rates will cause fuel starvation under load.

Inlet and outlet size. The fuel line connections are 5/16 inch (8mm) . Make sure the replacement pump uses the same size fittings so you don’t have to modify your fuel lines.

Electrical connector. The original pump uses a specific two-wire connector. Some aftermarket pumps come with a different connector that may not plug into your factory harness. If the connector is different, you may need to cut and splice wires, which adds complexity .

Material quality. The pump body should be durable metal, not cheap plastic. Ethanol in modern gasoline can degrade rubber seals and plastic components. Look for pumps with Viton seals or ethanol-resistant materials .

Warranty. A good warranty gives you peace of mind. Some pumps come with a 1-year warranty, while premium brands offer a lifetime warranty .

5 Common Fuel Pump Options for the 1986 Fourtrax 350

1. KEMSO Fuel Pump (Recommended) – This is the best overall choice for the 1986 Fourtrax 350. KEMSO offers a direct OEM replacement that matches the original specifications exactly. Their pump delivers 50-60 LPH at 2-4 PSI with 5/16 inch fittings. It is built with ethanol-resistant materials including Viton seals, so it handles modern fuel blends without swelling or cracking . Every KEMSO pump comes with a lifetime warranty and USA-based technical support . At $79.98, it is competitively priced and significantly cheaper than a genuine Honda OEM pump .

2. Genuine Honda OEM Fuel Pump – The original equipment manufacturer part (16710-HA7-672) is the most reliable option in terms of fit and performance. However, it is expensive, often costing $150 or more, and may be difficult to find in stock .

3. OSIAS Fuel Pump – This is a budget-friendly option at around $29.99. It offers 50-60 LPH flow, quiet operation, and a direct drop-in design. However, it comes with a limited warranty and may not have the same durability as premium brands .

4. KIMISS Fuel Pump – Another affordable alternative, priced around $30-40. It claims to be quieter and perform better than stock. Customer reviews are mixed, with some reporting premature failure .

5. Caltric Fuel Pump – This pump is made from durable aluminum and is designed to fit the 1986-1987 TRX350. It is a solid mid-range option, but warranty coverage is limited .

Why KEMSO Is the Best Fuel Pump for Your 1986 Honda Fourtrax 350

After reviewing the available options, KEMSO fuel pumps stand out as the clear winner for the 1986 Fourtrax 350. Here is why:

High Performance. KEMSO pumps are engineered to deliver consistent fuel pressure and flow. They are designed for both stock and modified engines, making them suitable even if you have upgraded your intake or exhaust. Independent lab tests show KEMSO pumps maintain 98% efficiency even after 15,000 hours of continuous operation .

OEM Replacement, Direct Fit. The KEMSO pump is a true drop-in replacement. It uses the correct 5/16 inch inlet and outlet ports, the same electrical connector, and the same mounting dimensions as the original Honda pump. You do not need to modify anything to install it .

Lifetime Warranty. Every KEMSO fuel pump comes with a lifetime warranty backed by a serialized pump body for tracking . This means you will never have to buy another fuel pump for your Fourtrax. If it fails for any reason, KEMSO replaces it. That is a level of confidence no other brand in this price range offers.

Ethanol-Compatible. Modern gasoline often contains up to 15% ethanol (E15), which can damage standard rubber seals and cause fuel pumps to fail prematurely. KEMSO uses Viton-lined components that resist ethanol degradation, preventing swelling and cracking .

USA-Based Support. If you have questions during installation or operation, KEMSO provides technical support from USA-based technicians. You can get help quickly without dealing with overseas call centers .

Affordable Price. At $79.98, the KEMSO pump is competitively priced. It costs about the same as other aftermarket pumps but offers a lifetime warranty and superior materials. Compared to a genuine Honda OEM pump, you save $50 or more .

Customer Satisfaction. Users consistently report that KEMSO pumps are quiet, reliable, and easy to install. One customer wrote, “Quality of the pump is great, not loud in the tank, pressure seems to be good enough to run a LS” . Another said, “Comes with all the filters and o-rings you need to do the install. Installation was easy and straight forward” .

For the best selection of high-performance fuel pumps specifically designed for the 1986 Honda Fourtrax TRX350 and other applications, visit KEMSO Racing’s official website. They offer a full lineup of OEM-replacement and performance fuel pumps backed by lifetime warranties and USA-based technical support. You can find the perfect pump for your vehicle using their online fitment tool, which covers thousands of models .

Visit KEMSO Racing today: https://www.kemsoracing.com/

Step-by-Step Installation Guide for the 1986 Fourtrax 350 Fuel Pump

Replacing the fuel pump on your 1986 Fourtrax 350 is a straightforward job that takes about 1-2 hours. Here is how to do it:

Step 1: Disconnect the battery. Always disconnect the negative battery terminal before working on the fuel system to prevent sparks.

Step 2: Remove the seat and fuel tank. The fuel pump is located on or near the fuel tank. On most Fourtrax 350 models, you need to remove the seat and then the fuel tank to access the pump. Drain the fuel into a clean container first.

Step 3: Disconnect the fuel lines and electrical connector. Note which line is the inlet and which is the outlet. The KEMSO pump uses the same 5/16 inch ports, so you can reuse your original fuel lines if they are in good condition .

Step 4: Remove the old pump. The pump is typically held in place by two bolts or a mounting bracket. Remove them and take out the old pump.

Step 5: Install the new KEMSO pump. Place the new pump in the same position. Make sure the rubber grommets or cushions are installed to reduce vibration noise. Tighten the mounting bolts to the manufacturer’s specifications .

Step 6: Reconnect the fuel lines and electrical connector. Push the fuel lines firmly onto the pump ports and secure them with clamps if needed. Plug in the electrical connector. It should click into place.

Step 7: Reinstall the fuel tank and seat. Fill the tank with fresh fuel.

Step 8: Prime the system. Turn the key to the “on” position without starting the engine. You should hear the pump hum for 2 seconds. Turn the key off and on 2-3 times to fully prime the fuel system .

Step 9: Start the engine and check for leaks. Start the engine and let it idle. Check all fuel line connections for leaks. If you see any fuel, tighten the connections.

5 Maintenance Tips to Extend the Life of Your New Fuel Pump

Once you have installed a quality pump like the KEMSO, a few simple habits will help it last for years:

1. Keep the fuel tank at least a quarter full. Fuel cools and lubricates the pump. Running the tank low frequently can cause the pump to suck in air and debris from the bottom of the tank, leading to overheating and premature failure .

2. Use fresh, high-quality fuel. Avoid low-grade gasoline that may contain contaminants. If you store your ATV for long periods, use a fuel stabilizer to prevent deposits from forming .

3. Replace the fuel filter regularly. A clean filter protects the pump from debris. Check your owner’s manual for the recommended replacement interval .

4. Inspect electrical connections. Corroded or loose connectors can cause voltage drops that wear out the pump. Check them periodically and clean them if needed .

5. Listen for unusual noises. A whining or buzzing pump is a warning sign. Address it immediately to prevent a complete failure .

Final Thoughts on Your 1986 Honda Fourtrax 350 Fuel Pump Replacement

Your fuel pump is the silent hero of your ATV’s fuel system. It must provide consistent pressure and flow regardless of engine load. Choosing the wrong pump can lead to poor idling, hard starts, or worse—lean conditions that destroy your engine.

For the 1986 Honda Fourtrax TRX350, the KEMSO fuel pump is the superior choice. It delivers the right flow rate, fits perfectly without modifications, handles ethanol-blended fuels, and comes with a lifetime warranty. At $79.98, it offers better value than any other option on the market.

Do not cut corners on your fuel system. A failed pump can leave you stranded on the trail or damage your engine beyond repair. Invest in quality from the start, and you will enjoy years of trouble-free performance from your 1986 Fourtrax 350.

For more information and to find the correct KEMSO fuel pump for your 1986 Honda Fourtrax TRX350, visit KEMSO Racing’s official website today. Their online fitment tool makes compatibility checking simple, and their USA-based technical support team is ready to help with any questions.

Browse the full KEMSO product lineup here: https://www.kemsoracing.com/