Mandatory E10 Fuel Starting June 2026: Is Your Motorcycle Ready?

Starting in June 2026, all fuel stations in Vietnam will be required to sell E10 gasoline, a mandatory blend containing 10 percent ethanol. Many riders are asking the same question: will this damage their motorcycle? Will the fuel tank rust? Will the carburetor clog?

The concern is well-founded. Ethanol in E10 attracts moisture, corrodes metal, degrades rubber, and builds up deposits in fuel systems more aggressively than pure mineral gasoline. Older carbureted bikes and motorcycles that sit unused are the most at risk, and most riders have not yet taken steps to protect against it.

This article covers the three main problems E10 causes in motorcycle engines and introduces two AMSOIL products that prevent damage before it starts: AMSOIL Quickshot for ongoing protection at every fill-up, and AMSOIL Gasoline Stabilizer for bikes in long-term storage.

1. Three Problems E10 Causes in Motorcycle Engines

Not every bike is affected equally. Understanding the mechanism helps you protect your motorcycle before problems develop.

1.1. Phase Separation — Ethanol and Water Splitting from Fuel

Ethanol continuously absorbs moisture from the air into the fuel tank. When enough water accumulates, the ethanol and water separate from the gasoline and sink to the bottom of the tank as a distinct layer. This is called phase separation.

When this ethanol-water mixture is drawn into the engine, it creates a lean-burn condition — the engine runs with too little fuel — causing combustion-chamber temperatures to spike and risking damage to pistons and valves. Bikes that sit unused for two weeks or more in humid conditions face the highest risk.

1.2. Corrosion of Fuel Tanks and Rubber Components

Ethanol is a powerful solvent that attacks materials throughout the fuel system:

• Metal fuel tanks on older bikes: causes internal rust
• Older rubber fuel lines: causes cracking, hardening, and flaking
• Carburetor gaskets and seals: causes swelling or shrinking, leading to fuel leaks

Carbureted bikes are the hardest hit. Fuel-injected bikes produced after 2015 generally use ethanol-compatible materials, but still benefit from ongoing protection.

1.3. Deposits in Fuel Injectors and Carburetors

Ethanol dissolves old deposits inside the fuel tank and carries them into the fuel system. These deposits accumulate on injectors, carburetors, and fuel filters, causing:

• Rough running and hesitation at low throttle
• Hard starting after the bike sits overnight
• Increased fuel consumption from an uneven fuel-air mixture

AMSOIL Quickshot — Protection at Every Fill-Up

AMSOIL Quickshot (product code AQSCN-EA) is a fuel additive designed specifically for powersports engines: motorcycles, clutch bikes, semi-automatics, scooters, and small-engine equipment. It is designed for regular use at every fill-up, not just as a one-time repair treatment.

Quickshot keeps water molecules dispersed evenly throughout the fuel rather than allowing them to accumulate and pull ethanol out of solution. The dispersed water passes out of the system as a normal part of combustion, eliminating the risk of phase separation before it can form.

Quickshot also cleans deposits from carburetors, injectors, spark plugs, and piston tops. Real-world testing on E10 fuel showed a 70 percent improvement in injector flow on plugged injectors and a 44 percent improvement in oxidation stability compared to untreated E10.

How to use:

• One 8-oz. (236-ml) bottle treats up to 6 gallons (~23 L) for a deep clean
• One 8-oz. bottle treats up to 12 gallons (~45 L) for ongoing protection
• Add to the tank before filling, at every fill-up for best results

AMSOIL Gasoline Stabilizer — Protection During Long-Term Storage

AMSOIL Gasoline Stabilizer (product code ASTCN-EA) is designed for bikes that sit for extended periods or need seasonal storage. E10 begins oxidizing and breaking down faster than pure mineral gasoline, forming varnish and gum in the fuel system in as few as 30 days of inactivity.

Gasoline Stabilizer keeps fuel stable for up to 12 months, while protecting fuel-system metals from ethanol corrosion. In the ASTM D525 oxidation stability test, AMSOIL Gasoline Stabilizer maintained stability for 4,320 minutes compared to 536 minutes for Sea Foam Motor Treatment — 8 times longer.

When to use Gasoline Stabilizer:

• Bikes ridden infrequently during the rainy season, parked for a month or more
• Preparing a bike for Tet holiday storage or an extended trip
• Rural bikes used only during harvest season and stored the rest of the year
• Older carbureted bikes: add to the final tank before storage to prevent carburetor varnish

How to use: One 16-oz. (473-ml) bottle stabilizes 38 liters or more of fuel. Add to the tank, start the engine and run for a few minutes to distribute the stabilizer through the entire fuel system before storing.

4. Quickshot or Gasoline Stabilizer? Or Both?

These two products serve different purposes and complement each other:

• Daily rider wanting ongoing protection: AMSOIL Quickshot at every fill-up
• Bike showing rough running or hard starts: AMSOIL Quickshot deep-clean dose (1 bottle per 6 gallons)
• Bike going into storage for 1 month or more: AMSOIL Gasoline Stabilizer before storing
• Bike used occasionally but not daily: Both — Quickshot at each fill-up, Stabilizer before seasonal storage

Owners of older carbureted bikes should prioritize AMSOIL Quickshot as soon as E10 becomes mandatory, since carburetors are prone to deposit buildup and cannot self-clean the way fuel injectors do.

Conclusion

Mandatory E10 fuel starting June 2026 is not a threat if you prepare correctly. AMSOIL Quickshot protects your motorcycle throughout daily operation by preventing phase separation and cleaning the fuel system at every fill-up, while AMSOIL Gasoline Stabilizer keeps E10 from degrading for up to 12 months when the bike needs to be stored. Both products are backed by independent test data and suited to the riding conditions in Ho Chi Minh City and southern Vietnam. Contact Huynh Chau Distributor for personalized advice on the right product for your motorcycle and riding habits.