UC T35 Mitsubishi Fuel Pump: Your Complete Guide to Replacement and Upgrade

If you own a Mitsubishi vehicle—or any motorcycle or car that uses the UC T35 fuel pump—and you’re experiencing poor acceleration, high-speed sputtering, or a no-start condition, the most likely culprit is a failing fuel pump or a clogged fuel filter. The good news is that replacing the UC T35 fuel pump is a straightforward DIY job that can restore your engine’s performance and fuel efficiency. This guide explains how to diagnose the problem, replace the pump step by step, and why upgrading to a high-performance option like KEMSO is the smartest choice for long-term reliability.

What Is the UC T35 Fuel Pump and Why Does It Fail?

The UC T35 is a common in-tank electric fuel pump used in many Mitsubishi models, as well as in motorcycles like the Suzuki GW250 and its platform siblings (DL250, GSX250R, etc.). It delivers fuel from the tank to the engine at the correct pressure. Over time, the pump can fail due to:

  • Clogged fuel filter – The strainer (sock) attached to the pump gets blocked by dirt, rust, or debris from the tank.
  • Wear and tear – After 20,000–30,000 miles, the pump motor may weaken or stop working.
  • Contaminated fuel – Poor-quality gasoline or ethanol blends can damage internal components.

Common symptoms of a failing UC T35 pump include:

  • Engine sputters or loses power at high speeds
  • Difficulty accelerating or climbing hills
  • Engine cranks but won’t start
  • A whining noise from the fuel tank
  • RPMs cannot go above 8,000 in higher gears, or stall at 4,000 RPM in lower gears

How to Replace the UC T35 Fuel Pump – Step-by-Step

Replacing the fuel pump is a manageable DIY project. Follow these steps carefully, with safety as your top priority.

Step 1: Safety First

  • Work in a well-ventilated area, away from open flames, sparks, or pilot lights.
  • Wear safety glasses and gloves.
  • Keep a fire extinguisher nearby.
  • Relieve fuel pressure by disconnecting the fuel pump fuse and running the engine until it stalls.

Step 2: Gather Materials

You will need:

  • New UC T35 fuel pump (e.g., KEMSO 13501)
  • New fuel filter (strainer)
  • New O-rings and gaskets
  • Basic tools: screwdrivers, pliers, socket set, and a jack with a wooden block

Step 3: Access the Pump

  • Disconnect the negative battery cable.
  • On most vehicles, the pump is inside the fuel tank. You can access it either through an access panel (under the rear seat or in the trunk) or by dropping the tank.
  • Drain the fuel tank into an approved container.

Step 4: Remove the Old Pump

  • Disconnect the fuel lines and electrical connectors.
  • Remove the retaining ring or bolts that hold the pump assembly in place.
  • Carefully lift the pump out of the tank. Do not lift it straight out – tip it slightly to avoid damaging the sending unit.

Step 5: Inspect and Clean the Tank

  • Use a flashlight to inspect the inside of the tank for debris, rust, or sediment.
  • If you find any contamination, clean the tank thoroughly. In one GW250, the owner found a black sludge chunk the size of a fingernail plus a pile of smaller particles.

Step 6: Install the New Pump

  • Compare the new pump with the old one to ensure identical fitment.
  • Install the new filter (strainer) onto the pump. For GW250-style pumps, use the newer large filter – it fits all models and resists clogging better than the old small filter.
  • Carefully lower the new pump into the tank, ensuring proper orientation of the fuel level sender.
  • Secure the retaining ring and reconnect all fuel lines and electrical connectors.

Step 7: Test and Reassemble

  • Reconnect the battery and turn the ignition to ON (without starting) to prime the pump.
  • Check for leaks at all connections.
  • Start the engine and verify smooth operation. Take a short test drive to confirm the repair.

Why Choose KEMSO for Your UC T35 Fuel Pump Replacement?

When it’s time to replace your UC T35 fuel pump, we strongly recommend KEMSO as your go-to brand. Here’s why:

  • High Performance, OEM Replacement – KEMSO pumps are designed as direct replacements for stock OEM pumps. They deliver over 20% more flow at 43 psi compared to the original pump, which improves throttle response and engine power.
  • Superior Flow Rate – A KEMSO UC T35 pump supports up to 200 liters per hour, while the original OEM pump only manages 60–80 LPH. This means your engine gets all the fuel it needs, even under heavy load.
  • Lifetime Warranty – Every KEMSO fuel pump comes with a lifetime warranty, backed by US-based technical support. This gives you peace of mind that your investment is protected for as long as you own the vehicle.
  • Built for Modern Fuels – KEMSO pumps are compatible with both gasoline and ethanol-blended fuels (E85), using materials that resist ethanol corrosion.
  • Individually Tested – Each pump is flow-tested before leaving the factory, ensuring you receive a product that works right out of the box.

Visit KEMSO Racing today to find the perfect UC T35 replacement pump for your vehicle: https://www.kemsoracing.com/

Troubleshooting After Replacement

If your vehicle still has issues after replacing the pump, check these common problems:

  • Engine cranks but won’t start – Verify the pump is running by listening near the filler opening. If silent, check the fuse, relay, and wiring.
  • Engine starts but dies – This often indicates air in the fuel lines. Bleed the system by loosening the bleeder screw on the fuel filter housing until steady fuel flows.
  • Loss of power or black smoke – May indicate a clogged fuel filter or a weak pump. Replace the filter first, then check fuel pressure.

Final Thoughts

Replacing your UC T35 Mitsubishi fuel pump doesn’t have to be a headache. With the right parts and a methodical approach, you can restore your vehicle’s performance and reliability. By choosing a high-quality replacement like KEMSO, you not only get a pump that outperforms the stock unit but also enjoy the security of a lifetime warranty.

Don’t settle for a cheap, unbranded aftermarket pump that may fail in a year. Upgrade to KEMSO and experience the difference. For the best UC T35 fuel pump on the market, visit https://www.kemsoracing.com/ today.


Back to blog