Honda string trimmers on the market today use 4-cycle engines. These types of engines have separate fill ports for gas and oil. Unlike string trimmers with 2-cycle engines, gas and oil are NOT MIXED for these types of engines.
Old gas is often the root cause of a starting or running problem. Purchasing the right gas and knowing how to care for it will help reduce fuel-related issues.
Honda string trimmers with 4-cycle engines require Regular Gas and 10W-30 engine oil.
- Gas: Unleaded regular gas with a minimum 87-octane rating and maximum 10% ethanol content.
- Engine Oil: Air-cooled 10W-30 engine oil with an API service category or SJ or later.
If you don’t have two-fill ports on your string trimmer, refer to your operator’s manual for fuel and oil requirements.
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Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
Old or Bad Gas in a Honda String Trimmer
When problems develop in your Honda string trimmer, old or wrong fuel is often the underlying cause of the problem. It can cause the trimmer to lose power, bog down, die, or not even start.
Gas can begin to break down and become less effective as quickly as 30 days after purchase. Ethanol, an alternative fuel added to gas, is not good for the small engine on a trimmer.
This is because ethanol naturally attracts moisture to the fuel system. This moisture and ethanol mixture will leave behind varnish and sticky deposits that may restrict fuel flow and cause component failures.
It is also corrosive to the fuel system and engine.
Because of its negative effects, never use gas with an ethanol content greater than 10%.
Use Fresh Fuel and a Fuel Stabilizer:
Because gas breaks down quickly, it is important to purchase fresh gas and consume it within 30 days. Add a fuel additive like Sea Foam Motor Treatment to stabilize the gas and reduce moisture so it lasts a little longer.
Fuel stabilizers cannot reverse the effects of old fuel. Add fuel stabilizers to fresh gasoline.
Use of Ethanol-Free Fuel for Honda String Trimmers:
To avoid the negative effects ethanol has on a Honda engine, you may choose to use an ethanol-free fuel. You can find these fuels online and at your local hardware store.
Having fuel on hand is a convenient option so they are ready when you need them. However, these are the most expensive options to fuel a trimmer.
Gas and Oil to Use in a 4-Cycle Honda String Trimmer
Gas for Honda 4-Cycle String Trimmer
Honda 4-cycle engines have separate fill ports for fuel and oil so there is no need to mix them.
4-cycle Honda string trimmers require unleaded gasoline with an octane rating of 87 or higher and an ethanol content of 10% or less.
It is best to add a fuel stabilizer like Sea Foam or STA-BIL to keep the gasoline from breaking down quickly and to help reduce moisture and gummy deposits in the fuel system.
While using gasoline with a low ethanol content is acceptable, it is not the best option available.
The best fuel to use in a Honda string trimmer is an ethanol-free fuel available at the fuel pump at select fuel stations or in canisters at your local hardware store or online.
Ethanol-free gas is the more expensive choice. Purchasing in canisters is not only convenient, but it may also be a good alternative if you don’t want to deal with the potential headaches that can come from running old ethanol-based gas through a string trimmer.
Engine Oil in a 4-Cycle Honda String Trimmer
4-cycle engines have separate fill ports for the engine oil and the fuel. DO NOT mix the oil and fuel together for a 4-cycle engine. Never use 2-cycle oil in a 4-cycle string trimmer.
Oil is required to keep the engine components lubricated. When the wrong type or not enough oil is used, friction can build in the engine and overheat causing your string trimmer not to start and possibly ruin the engine.
Honda recommends using an SAE 10W-30 engine oil. A good air-cooled engine oil like this one by Kawasaki works well.
4-Cycle Honda Engine Oil Viscosity
The fuel used in your Honda string trimmer affects performance. When fuel ages, it can cause corrosion and fuel restrictions.
Follow these simple steps when choosing a fuel for your Honda string trimmer:
- Always use fresh gas.
- Make sure the gas contains no more than 10% ethanol and a minimum 87-octane rating.
- Know the type of engine on your string trimmer
- 4-cycle: Use straight gas.
- Add a fuel stabilizer so your gas has a longer shelf life without breaking down.
- Store gas in a dry location away from moisture and combustible products.