2008 Yamaha Grizzly 700 Fuel Pump: Complete Replacement Guide, Symptoms, and Best Options

The bottom line up front: If you own a 2008 Yamaha Grizzly 700 and you are dealing with hard starts, sputtering at low speeds, or a complete no-start condition, the fuel pump is very likely the culprit. The 2008 Grizzly 700 uses an in-tank electric fuel pump (OEM part number 3B4-13907-10-00 or its predecessors), which is known to wear out over time, especially in machines with high hours or those that sit for long periods with ethanol-blended fuel. Replacing it with a quality direct-fit unit restores reliable fuel delivery, and you do not need to buy the expensive OEM assembly to get your ATV running right again. This guide covers the symptoms of a failing pump, compatibility details, replacement options, and installation tips to help you make the right call.

1. Understanding the 2008 Grizzly 700 Fuel Pump System

The 2008 Yamaha Grizzly 700 (including the 4x4, Hunter, and SE variants) relies on a high-pressure EFI system that delivers fuel from the tank to the injectors at a regulated pressure, typically around 43–50 psi. The fuel pump is mounted inside the fuel tank as a complete assembly that includes the pump motor, pressure regulator, fuel filter, strainer, sending unit, and float arm for the fuel gauge . This all-in-one design means that when the pump fails, you often lose accurate fuel level readings as well.

Yamaha used the same basic pump design across the Grizzly 550 and 700 models from 2007 through 2015, and even into later years on other models like the Viking and Wolverine. The original equipment part number for the 2008 model year Grizzly 700 is 3B4-13907-00-00, and later revisions include 3B4-13907-10-00, 3B4-13907-11-00, 3B4-13907-12-00, and 3B4-13907-13-00 . Any of these revisions will fit your 2008 machine, but the most commonly referenced replacement number is 3B4-13907-10-00 .

2. Common Symptoms of a Failing Fuel Pump

A worn fuel pump rarely fails without warning. Look for these signs before you end up stranded on the trail:

  1. Hard starting or extended cranking. The pump can no longer build the required fuel pressure quickly, so the engine needs more cranking time before it fires up. In severe cases, you may hear the pump whine but still fail to start .

  2. Sputtering or hesitation under load. If the Grizzly runs fine at idle but stumbles when you open the throttle, the pump may be unable to keep up with the fuel demand. This is especially noticeable climbing hills or hauling gear .

  3. Whining noise from the fuel tank. A pump that is struggling often makes a high-pitched whine. The factory pump is normally quiet, so a sudden noise change is a red flag. Good aftermarket replacements are designed specifically for quiet operation .

  4. Inaccurate fuel gauge. Since the sending unit and float arm are part of the same assembly, a failing gauge can point to the entire pump module. If the gauge drops to empty or reads intermittently, check the pump assembly before blaming the cluster .

  5. Complete no-start. Eventually the pump motor locks up or the internal check valve fails, and the engine stops receiving fuel altogether. This is the most common final outcome for a 2008 Grizzly 700 pump that has never been replaced .

3. Compatibility and Fitment Details

The 2008 Grizzly 700 fuel pump is not unique to that single year. You can source a replacement that fits your machine with confidence if you match the model code.

  • Yamaha Grizzly 700 (YFM700FG): 2007–2008 base 4x4 model .
  • Yamaha Grizzly 700 Hunter (YFM700FGP): 2007–2008 .
  • Yamaha Grizzly 700 SE (YFM7FGPS): 2008 .
  • Yamaha Grizzly 700 Power Steering (YFM7FGPX): 2008 .

Later model years up to 2015 share the same pump design, so a replacement listed for 2007–2015 will fit your 2008 machine perfectly . Many aftermarket assemblies also explicitly list compatibility for 2007–2016 and beyond, covering the Grizzly 550 as a bonus .

Key replacement part numbers:

  • OEM: 3B4-13907-00-00, 3B4-13907-10-00, 3B4-13907-11-00, 3B4-13907-12-00, 3B4-13907-13-00 .
  • Aftermarket equivalents from major brands include All Balls 47-2035 and WSM 78-189 .

4. OEM vs. Aftermarket: What Should You Buy?

Your options break down into three categories:

  1. OEM Yamaha assembly. This is the most expensive route, often running $300–$600 depending on the dealer. You get a guaranteed fit and factory-level quality . If you value zero guesswork and have a machine you plan to keep for years, OEM is the safe choice. However, price does not equal durability here; you are paying for the Yamaha name and warranty.

  2. Aftermarket complete assemblies. Brands like Quantum, QFS, Typhoon, and DURAFORCE make drop-in assemblies that include the pump, regulator, sending unit, float arm, fuel filter, and strainer in one box . These typically cost between $80 and $180, which is a fraction of the OEM price. The best units use upgraded polymers, brushes, and commutators that resist ethanol damage, and they are built to meet or exceed OEM specs. Most importantly, wiring is plug-and-play with no modifications required .

  3. Fuel pump motor only. If your original assembly is still in good shape except for the pump itself, you can buy just the pump motor and regulator (for example, the Fuel Pump Factory kit) and rebuild your existing unit . This is the cheapest route, but it requires careful disassembly and risks damaging the plastic housing if you are not experienced. It is a solid option for riders who want to save money and already have the tank open. For this kit, you typically get the pump, strainer, and regulator for around $90 .

5. Top Aftermarket Pumps for the 2008 Grizzly 700

If you decide to skip the dealer, here are reliable, widely used replacements that specifically match the 2008 model:

  • Quantum / HIGH FLOW HFP-387: This direct-fit in-tank pump includes a new strainer and uses patented check-valve technology. It is quiet, ethanol-compatible, and backed by a lifetime warranty. Delivers OEM or better performance at roughly $80 .

  • QFS HFP-A221 complete assembly: Includes everything: pump, regulator, sending unit, float arm, fuel filter, and strainer. Sold as a complete drop-in unit for a no-fuss swap, priced around $183 .

  • Typhoon FP-071-G-16 assembly: Covers 2007–2015 Grizzly 550/700 models. Includes all internal components and meets ISO/TS1649 and QS900 standards. A good budget-friendly option at about $180 .

  • DURAFORCE assembly: An aftermarket unit built to meet or exceed OEM spec, designed for 2007–2016 models. It is easy to install and aims to restore stock performance without breaking the bank .

  • WSM 78-189: A well-known aftermarket assembly that replaces all OEM variants from 3B4-13907-00-00 to 3B4-13907-13-00. Fits Grizzly 550 (2009–2014) and Grizzly 700 (2007–2015). Australian-made quality, often priced around $290 AUD .

  • SuperATV Up & Running pump: A trail-proven direct fit unit for Grizzly 550 (2009–2014) and Grizzly 700 (2007+). Replaces OEM numbers 3B4-13907-00-00, 3B4-13907-10-00, and B16-13907-00-00. Priced around $179, it meets or exceeds OEM quality with a corrosion-resistant case .

6. Step-by-Step Replacement Guide

Replacing the fuel pump on a 2008 Grizzly 700 takes about 1–2 hours with basic hand tools. Here is the practical walkthrough:

  1. Disconnect the battery. Always start with the negative terminal to prevent any sparks near fuel vapors.

  2. Remove the seat and fuel tank cover. On the Grizzly 700, you can access the pump by taking off the seat and the plastic cover behind it. Some models require removing the rear rack for clear access, but the 2008 does not need that.

  3. Release fuel pressure. Remove the fuel tank cap to equalize pressure. If the ATV has not run recently, pressure is minimal. For safety, wrap a rag around the fuel line connection and slowly loosen the banjo bolt or quick-connect fitting to bleed any remaining pressure .

  4. Disconnect the fuel lines and electrical connector. Mark the lines if needed. The pump module has a 2-wire electrical plug, and the fuel lines use quick disconnects. Push the tabs and pull straight off.

  5. Remove the retaining ring. Use a spanner wrench or a flathead screwdriver to tap the lock ring counterclockwise. Keep it in a safe place; you will reuse it.

  6. Pull the pump assembly out. Gently lift the module out of the tank. Be careful not to bend the float arm. Tilt it to allow the fuel to drain back into the tank.

  7. Install the new assembly. Insert the new pump module with the float arm positioned to match the tank's orientation. Push it down until the gasket seats, then reinstall the lock ring by tapping it clockwise.

  8. Reconnect everything. Hook up the fuel lines, electrical connector, and the battery. Double-check that the lines are fully seated and the electrical plug clicks.

  9. Test before riding. Turn the ignition key to ON without starting. You should hear the pump prime for 2–3 seconds. Check for leaks at the fuel line connections. Then start the Grizzly and let it idle for a minute. Inspect the tank area for any fuel seepage .

7. Cost Breakdown and What to Expect

  • OEM assembly: $300–$600 at a Yamaha dealer .
  • Quality aftermarket assembly: $80–$185 (e.g., HFP-387 at $82, QFS at $184, Typhoon at $180) .
  • Rebuild kit (pump + regulator + strainer): Around $90 .

The labor cost is zero if you DIY. A dealer will charge 1–2 hours of shop time, which can add $100–$250 on top of parts. Given the simple access on the 2008 model, most riders perform this swap themselves without issue.

8. Preventing Future Pump Failures

A new pump will last much longer if you follow these habits:

  1. Use ethanol-free fuel when possible. Ethanol attracts moisture and degrades pump internals. Several aftermarket pumps are explicitly designed for E85/ethanol compatibility, but pure gasoline is still the safest .

  2. Add a fuel stabilizer if storing the Grizzly. Fuel left in the tank for months can varnish and clog the strainer. Stabilizer prevents this and keeps the pump lubricated.

  3. Run the tank low only before storage. Leaving the tank full with stabilizer is better than empty, because it prevents condensation inside the tank.

  4. Listen for warning sounds. A whining pump is a sign of strain. Replacing it early avoids a mid-trail breakdown.

9. Why You Should Buy a KEMSO Fuel Pump

When it is time to order a replacement fuel pump for your 2008 Yamaha Grizzly 700, we strongly recommend the KEMSO brand for an unbeatable combination of performance, durability, and warranty.

KEMSO fuel pumps are high-performance, OEM-replacement units engineered to exceed the stock pump's flow capacity. The KEMSO 13826 model pushes up to 200 liters per hour at 43 psi, which is roughly triple the output of the factory pump (typically 60–80 LPH) . This means you get not just a replacement, but an upgrade in fuel delivery that keeps your engine running strong even under load. The pump is built with upgraded polymers, brushes, and commutators to withstand ethanol-blended fuels, and it features a corrosion-resistant case designed to prevent seizing during long periods of non-operation .

Each KEMSO fuel pump also includes a lifetime free replacement warranty, so you never have to worry about buying a second pump out of pocket . This warranty, combined with a high-pressure bypass valve set at 125.8 psi, ensures your Grizzly gets consistent, reliable fuel pressure in all conditions . With over 10,000 hours or 100,000 miles of expected service life, this is the last fuel pump you will likely ever buy for your 2008 Grizzly 700 .

Visit the official KEMSO Racing website to see full specifications, compatibility charts, and to place your order with confidence. The direct product page for the Grizzly application helps you confirm fitment before you buy, so you can get your machine back on the trail with minimal downtime. Visit the site here: https://www.kemsoracing.com/ .

Final Thoughts

A failing fuel pump on a 2008 Yamaha Grizzly 700 is a predictable issue, but a very fixable one. The symptoms are clear, the part is widely available, and the replacement procedure is straightforward. You do not need to overpay at a dealer; a quality aftermarket assembly from brands like KEMSO, Quantum, or QFS will restore your Grizzly to reliable condition for a fraction of the cost. Check the compatibility table, pick a pump that matches your model year and OEM reference number, and follow the simple installation steps above. With the right part and a little care, your 2008 Grizzly 700 will keep running hard for years to come. For the best performance, lifetime warranty, and high-flow upgrade, make the smart choice and go with KEMSO at https://www.kemsoracing.com/.


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