Yamaha MZ360, MZ400 Owner's Manual
![Yamaha MZ360, MZ400 manual cover](/images/c87ec9b1d3b0119512fa3ebd/thumbs/thumb175x175.webp)
It is recommended to use a high-quality SAE 10W-30 or 10W-40 engine oil for the Yamaha MZ360 and MZ400 engines. Ensure that the oil meets API service classification SJ or higher.
For optimal performance, the oil should be changed every 100 hours of operation or at least once a year, whichever comes first. Always check the oil level before each use.
The correct spark plug gap for the Yamaha MZ400 engine is 0.7 to 0.8 mm (0.028 to 0.031 inches).
If the Yamaha MZ360 engine won't start, check the fuel level, ensure the spark plug is clean and properly gapped, verify that the air filter is not clogged, and make sure the engine switch is in the "ON" position.
Before storing the Yamaha MZ400 engine for an extended period, drain the fuel tank and carburetor, change the engine oil, remove the spark plug and add a few drops of oil into the cylinder, and store the engine in a dry place.
To adjust the idle speed on the Yamaha MZ360 engine, locate the idle adjustment screw on the carburetor. Turn the screw clockwise to increase idle speed and counterclockwise to decrease it until the desired idle speed is achieved.
To clean the air filter on a Yamaha MZ400 engine, remove the air filter cover, take out the air filter, and clean it with a mild detergent and water. Allow it to dry completely before reinstallation. If the filter is damaged, replace it.
To check the engine oil level on a Yamaha MZ360, ensure the engine is on a level surface, remove the dipstick, wipe it clean, insert it back without screwing it in, and then remove to check the oil level. Ensure the level is between the low and high marks.
Black smoke from the exhaust of a Yamaha MZ400 engine usually indicates a rich fuel mixture. Check the air filter for blockages and ensure the carburetor is adjusted properly. Also, inspect the choke operation and fuel quality.
To break in a new Yamaha MZ360 engine, operate the engine at varying speeds and loads for the first 20 hours. Avoid running at full throttle for extended periods. Change the oil after the initial break-in period.