Motor Oil and Fuel Service
We have provided you the Parsun Outboard Manual, Parts Catalog, and DIY Service Guides. Those documents will help you operate and maintain Parsun 4-stroke outboards. If you have sufficient outboard motor knowledge and experience, you can service the Parsun outboard by yourself.
(1) A 4-stroke motor is very different from a 2-stroke outboard motor. It is important to use the proper 4-stroke motor oil in the motor’s sump (engine) before starting the motor. A 4-stroke motor’s internal/external fuel tank only uses pure gasoline (87 to 94 octane). Do NOT put any mixture of gasoline and motor oil in the fuel tank. Do NOT use 2 stroke fuel which is a mixture of oil and gas for your new 4 stroke motor. If you have an existing portable fuel tank with 2 stroke motor fuel, please empty the portable fuel tank before using it for this new Parsun 4 stroke motor. It is best to use marine gasoline fuel or automobile gasoline that does not contain ethanol. Ethanol and water from the fuel will hurt the carburetor and fuel system. This damage is not covered by the Parsun Limited Warranty.
(2) Only use 4-stroke motor oil in Parsun 4-stroke gas motors. Using the wrong types of engine oil such as 2-stroke motor oil or Diesel motor oil will damage your 4-stroke motor and void the manufacturer limited warranty.
Suggested 4-stroke Motor Oil:
Yamalube Four-Stroke Marine Performance FC-W 10W-30 (Yamaha)
Mercury 4 Stroke Outboard Oil SAE 10W-30 (FC-W)
Other Marine 4 Stroke Motor Oil 10W-30
Suitable Motor Oil:
Four-Stroke Motor Oil SAE 10W-30 / 5W-30 (Castrol, Mobile, Pennzoil, Quaker State, Shell)
(3) Flush Fuel System
In case of mistakenly adding a mixture of gasoline and motor oil into a 4-stroke motor's fuel system, users can check the following DIY steps.
Fuel System Flush Instructions for a Motor with an Internal Fuel Tank (2.6HP, 4HP, 5HP, 6HP).
- Use a portable fuel pump to pump all the fuel out of the tank or remove the bolts holding the fuel tank in place. Remove the fuel tank from its original position then place the internal fuel tank upside down into an empty container to empty the tank.
- Loosen the copper drain bolt located at the bottom of the carburetor with a flat screw driver. Drain out all the fuel from the carburetor. Hand tighten the drain bolt to its original position.
- Fill a small amount of pure gasoline into the internal tank. Repeat above steps if necessary.
Fuel System Flush Instructions for a Motor with a Fuel External Tank (8HP, 9.8HP, 15HP, 20HP or up).
- Use a portable fuel pump to pump all the fuel out of the tank or place the fuel tank upside down into an empty container to empty the tank. Put a small amount of pure gasoline into the external tank to flush it.
- Loosen the copper drain bolt located at the bottom of the carburetor with a flat screw driver. Drain out all the fuel from the carburetor.
- Fill up the external fuel tank with pure gasoline. Use the fuel pump attached to the fuel line to pump the new gasoline to the motor. Stop pumping when another 100ml fuel drain out from the carburetor.
- Repeat above steps if necessary.
Drain & Flush the Carburetor
- Have a small container placed under the carburetor’s drain hole (spring water bottle)
- Slowly loosen the drain screw but it is not necessary to completely remove the drain screw from its position.
- Let the fuel come drain slowly. Check the drained fuel for contaminates and fuel color.
- If the internal tank is used, first close the fuel cock of the internal tank and fill the tank with pure gasoline. Slowly open the fuel cock switch, wait for 50ml gasoline to come out from the carburetor’s drain hole. (For 6HP model, you can also push the front built in fuel pump).
- If the external tank is used, slowly press the inline fuel pump attached to the fuel line until approximate 100-150ml of clear gasoline comes out from the carburetor's drain hole.
- Very slowly, pull the starter cord to ensure the internal fuel pump is working. It will force the fuel to move into the fuel system. Do NOT pull the cord with full strength or too fast.
- Tighten the drain screw to its original position. Make sure there are no fuel leaks or fuel sitting around the engine (as this may start a fire) before closing the motor cowling.
Download Parsun Motor Oil and Fuel System DIY Service Guide
Download Parsun Outboard Motor Inspection Report
Motor Winterize Service
To help keep your engine in tip-top condition for years to come, it is important that you “winterize” your outboard for off-season storage. By winterizing your outboard, you will help ensure that your outboard will be ready to go at the start of next year's boating season.
This guide provides basic information about how to prepare Parsun 4-Stroke motors for a two months or longer periods of storage or winterize. It is necessary to follow the procedure to prevent excessive damage to the motor. For details, please refer to the corresponding sections in the owner manual.
CAUTION - Always do the following DIY procedures in a safe, open and non-smoking large outdoor area. Keep children away. Get some containers, shop towels and a working fire extinguisher (Class B) ready to be used. Wear proper personal protective equipment (PPE). Users must preview every DIY step before starting. Users are solely responsible for performing the following DIY steps and their consequences. Otherwise, users shall take their outboard motor to a local certified marine shop or certified outboard technician for service.
Ready to Start
Keep the motor in an upright position on a motor stand or your boat. Use fresh water to wash the motor surface below the cowling rubber seal line. Wipe off dirt and debris on the motor surface. Flush the Cooling System 2.6HP, 5HP, 6HP models
- Have a large enough bucket filled with fresh water to cover 4 inches of the water intake on the motor leg.
- Start the motor and let it run at a normal idle speed for about 5 minutes. The fresh water in the tank will flush the motor’s cooling system. It is necessary to maintain the fresh water line above the anti-cavitation plate.
- Check and make sure the motor running is smooth and the sound of engine is normal. Limit engine's RMP to 2000 max or 35% of the full throttle.
- Always make sure there is enough fresh water in the bucket for motor water pump located the lower leg unit.
8HP, 9.8HP, 15HP, 20HP models
- Have a set of “ear muffs” style flushing equipment connect to water hose and cover the motor’s water intake.
- May also connect the water hose to the water pipe connector, if equipped. For example, the 20HP models.
- Start the motor and let it run at a normal idle speed for about 5 minutes. The fresh water coming from “ear muffs” will flush the motor’s cooling system.
NOTE - Parsun outboards are water cooled. Running your outboard without an adequate source of cooling water will result in severe damage to the motor.
Change Motor Oil
- Review the owner’s menu “Changing Engine Oil” Section or “Parsun Motor Oil & Fuel Service Guide”
- Locate the engine oil drain hole. Have the drive socket set, used oil container and glove ready.
- Slowly remove the motor oil drain screw and drain all motor oil. Best to have the motor in warm up condition.
- Change Motor oil filter, if equipped. (15HP, 20HP models)
- Make sure the engine is dry out with motor oil, Insert and tighten the drain screw slowly and correctly. Don’t lost the washer or damage the threads in the drain hole.
- Fill proper amount of pure 4-Stroke motor oil into the sump. The amount of motor oil can be found from the label on the engine.
- Only use 4 stroke outboard motor oil 10W-30 or 5W-30. Do NOT put any gasoline or wrong type of oil into the sump.
- Lubricate the rubber gasket on the new filter with a little fresh engine oil to assure a proper seal, and then install by hand tightening the filter to specification (15&20HP)
NOTE: If you laid down the motor on the wrong side, or over-fill the motor oil, it will cause motor oil leakage out of the engine and into the cylinder. Clean up the motor surface, you can stop the leakage by putting the motor upright or adjust the motor oil level. If there is too much oil in the cylinder, you need to clean up the spark plug before you can start the motor. Please understand a small amount of smoke from the exhaust system will last for a few seconds if oil leaked into the cylinder. No additional service is required if you can start the motor. Change Gear Oil in the Lower Unit
- Get the recommended outboard gear oil (Mercury, Yamaha) and gear oil pump ready. Till the motor to set the gear oil drain screw at the lowest point.
- Place an empty container under the motor’s lower unit for recycling the used gear oil. Remove the Gear Oil Drain Screw from the lower unit of the leg. Remove Gear Oil Level Screw to completely drain all gear oil.
- Check / replace the seal washers. (seal washer can be found from new motor package or any outboard dealer shop).
- Use gear oil pump to connect Gear Oil Drain hole, inject gear oil into the gear box. Insert and tighten the gear oil screw when the oil begins to flow out from the oil level screw hole. Insert and tighten the gear oil drain screw. Apply Fogging Oil (Storage Oil)
- Have a fogging spray can ready. It is recommended to purchase one from a local marine shop. You can ask for detailed products and instructions from the staff. Remove the motor cowling. Start the motor and let it run.
- Spray proper amount of fogging oil into the motor’s air intake while the motor is running. Follow the fogging oil manufacturer’s recommended amount.
- When the fogging oil is sprayed into the running motor’s cylinder(s), it is not uncommon to see excessive smoke from the exhaust. It may last for a few seconds to several minutes depending on how much fogging oil sprayed into the cylinder(s).
Drain the Carburetor (VERY IMPORTANT)
- If external tank is used, disconnect external fuel line to the motor.
- Run the motor until it runs out of fuel. As the fuel begins to run out and the motor starts to "die", choke the engine a little until the mMs pick back up. Continue choking the engine as the engine starts to die out until the fuel supply is finally exhausted.
- Slowly loosen the carburetor’s drain screw to let all the fuel drain out. Note: Drain screw and drain hole of Parsun 2.6HP motor are located at the bottom of carburetor.
- Change or clean the gasoline filter if equipped.
- If you have fuel left in your tank, add Fuel Stabilizer to it and fill the tank to keep condensation and evaporation to a minimum so that it can be used the following season.
It is important to completely drain the fuel system before storing the motor for prolonged period. Otherwise, deposits may form inside the carburettor and block the fuel system. This issue will not be covered by Parsun Limited Warranty. Apply Grease
- Tilt the engine up and use a grease gun charged with marine grease to lubricate all grease fittings. There is one on each side of the steering slide forward of the engine, another found on the steering column, and one on the shift mechanism where the shift cables enter the cowling.
- Spray the engine and rubber components with a liberal application of Silicone Engine Protectant and Lubricant. Once the boat gets to its final winter resting spot, trim the engine full “in” for storage and disconnect the negative battery cable(s). Battery Storage
- Disconnect the battery cables and clean the battery terminals using a wire brush. Recharge the battery to full strength. You should also recharge the battery once a month during the off-season to prevent electrical discharge and degradation of the electrolytes.
- Clean the exterior of the battery. Apply grease (Vaseline works nicely) to the battery terminal. Store your battery in a dry and cool place. Do not allow the battery to freeze. Storing the Motor
- Plan a dry, well ventilated, and covered place without direct sunlight to store the motor. Have a sturdy and stable motor rack hold the motor in upright position, or laid it down at a proper position (tiller handle side down position)
- Keep your storage temperature 5-15°C (40-60°F). Motor and fuel tank should be away from any heat source. Factors to Keep in Mind
- Storing in water allows algae and corrosion to affect your outboard. Storing out of the water could cause damage if the outside temperature reaches freezing and there is water in your lower unit.
- If you store your motor tilted up, we recommend you remove your prop to decrease the temptation of someone stealing your prop. Storing your outboard motor down in the salt water drastically increases the potential for corrosion. Download Parsun Motor Winterize Service Guide Download Parsun Outboard Motor Inspection Report