Subsequent valve mechanism inspections will be made at which interval after the initial 25-hour inspection?

• A. 25 hours
• B. 50 hours
• C. 100 hours
• D. 150 hours

Answer: (C)

The interval being tested is about how often valve clearances are checked after the initial setup. After the early 25-hour inspection, the standard maintenance practice is to recheck the valve mechanism every 100 hours. The reason is that during break-in, wear can change more quickly and needs close monitoring, while once the engine has settled, wear typically progresses more slowly, allowing a longer, regular interval. Valve clearances can drift with use, heat, and seating, so sticking to a 100-hour schedule helps catch any out-of-tolerance conditions before they affect performance or reliability. If a valve is found out of tolerance, it’s addressed then and the schedule may be adjusted based on the result.