I. Problem Overview
During operation, flywheel oil slinging can lead to abnormal lubricant consumption, potentially causing a decline in equipment performance and even affecting normal mechanical operation. Therefore, understanding the primary causes of this issue and implementing appropriate countermeasures is crucial. Below is a detailed analysis of common problems and corresponding solutions.

II. Problem Analysis and Solutions

1. Blow-by Gas Entering the Crankcase(Excessive Crankcase Backpressure)
(1)Causes of the Issue：
When combustion gases enter the crankcase, internal pressure may increase, causing lubricant to seep from the flywheel area. This issue can arise due to wear on the cylinder liner, piston, or piston rings, leading to poor sealing and allowing combustion gases to leak into the crankcase.

(2)Solutions：
a.Inspect Related Components:
Check the condition of the cylinder liner, piston, and piston rings to ensure they are not excessively worn or seized.
b.Replace Faulty Parts:
If sealing components are aged or if piston rings and labyrinth oil seal rings are worn, they should be replaced promptly to restore sealing performance.
c.Contact YANMAR Technical Support:
If the issue cannot be resolved independently, it is advisable to consult professional technicians for further inspection and repair.

2. Clogged or Excessively Bent Crankcase Vent Pipe
(1)Causes of the Issue：
The gases inside the crankcase must be properly vented to maintain optimal pressure. If the vent pipe is clogged or contains excessive bends, gases cannot be efficiently discharged, leading to increased internal pressure and lubricant leakage.

(2)Solutions：
1.Clean the Vent Pipe: Regularly inspect the vent pipe for blockages and remove any accumulated dirt or sludge.
2.Improve Vent Pipe Design: If excessive bends are present, consider replacing the pipe with one of an appropriate diameter to ensure smooth gas flow.
3.Contact YANMAR Technical Support: If the issue persists, seek assistance from a professional technician for system adjustments or modifications.

3. Overfilling of Lubricant
(1)Causes of the Issue：
Excessive lubricant addition may cause pressure changes during operation, leading to oil seepage from seals or vent holes. Overfilling can also increase internal operating resistance, negatively affecting mechanical efficiency.

(2)Solutions：
1.Adjust Lubricant Volume: Ensure that the amount of lubricant added adheres to the equipment’s standard recommendations.
2.Check the Dipstick: Refer to the oil dipstick markings when adding lubricant to prevent overfilling.
3.Regular Maintenance and Monitoring: Periodically inspect lubricant levels during equipment operation to prevent overfilling.

4. Worn Flywheel Labyrinth Oil Seal Ring or Clogged Oil Return Passages
(1)Causes of the Issue：
1.If the labyrinth oil seal ring is worn, the clearance between the seal ring and the main shaft journal increases, leading to oil leakage.
2.If the oil return passage is clogged, the lubricant cannot return to the crankcase, causing it to be slung out of the flywheel. This issue is commonly found in engines using heavy oil or those that have been idle for extended periods.

(2)Solutions：
1.Replace the Flywheel Labyrinth Oil Seal Ring: Before replacement, measure the crankshaft deflection to determine if there is any excessive deviation. When replacing the oil seal ring, ensure that the clearance between the seal ring and the main shaft journal is properly adjusted (refer to the manufacturer’s maintenance manual for specifications).
2.Clear the Oil Return Passage: If clogging is detected, clean the passage to restore proper lubricant flow.

III. Conclusion and Recommendations
Flywheel oil slinging is often related to internal pressure issues, wear of the flywheel labyrinth oil seal ring, and improper lubricant levels. Implementing appropriate maintenance measures—such as regularly inspecting the flywheel labyrinth oil seal ring, cleaning the vent pipe, and properly controlling lubricant levels—can significantly reduce the occurrence of this issue. Additionally, if the problem exceeds general maintenance capabilities, contacting a technical support representative is recommended to ensure optimal equipment operation.