Yanmar 4TNE88 — Adjusting the valve head clearance
Adjustments · Valve rocker arm / valve cap
For the Yanmar 4TNE88, from the Yanmar service manual.
Applies to: Yanmar 4TNE88, Yanmar TNE series engine
Before you start
- If the valve cap is worn or damaged on the head, replace it with a new one.
- Make sure the valve cap is nested on the head of intake/exhaust valves.
Procedure
- Inspect and adjust the valve head clearance while the engine is cold.
- Raise the piston of the cylinder to top dead center (TDC) of compression.
- Loosen the lock nut and adjusting screw; ensure the valve cap is free from inclination or dirt.
- Insert a thickness gauge between rocker arm and valve cap.
- Tighten the adjusting screw until clearance is attained.
Tools required
- Thickness gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake/exhaust valve head clearance 0.15~0.25 mm (all models)
Full service-parts list: Yanmar 4TNE88 →
Source: Yanmar service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.