Yanmar — Measuring Compression Pressure
Testing & diagnosis · Engine Cylinder
From a Yanmar service manual covering: YDG2700, YDG2700EV-6EH, YDG2700EV-G6EH, YDG2700EV-GEH, YDG3700, YDG3700EV-6El, YDG3700EV-GEI, YDG5500, YDG5500EV-6El. Check it applies to your exact model before use.
Applies to: Yanmar YDG2700, Yanmar YDG2700EV-6EH, Yanmar YDG2700EV-G6EH, Yanmar YDG3700, Yanmar YDG5500, Yanmar L70V engine, Yanmar L100V engine, Yanmar L4sV L70V L100V engine
Before you start
- NEVER touch hot engine surfaces during operation and shortly after shut-down.
Procedure
- Warm up the engine.
- Stop the engine and remove the fuel injector from the cylinder head.
- Crank the engine with the speed control at the stop position 5 to 6 compression strokes.
- Install a gasket at the tip of the compression gauge adapter.
- Install the compression gauge and adapter at the cylinder.
- Crank the engine until the compression gauge reading is stabilized and at its maximum.
- Remove the gauge and adapter; install the fuel injector and high pressure fuel injection line.
Tools required
- Compression Gauge Kit (Yanmar Gauge Set Code No. TOL-97190080) Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Standard 427 psi (2942 kPa, 30 kgf/cm2); Limit 356 psi (2452 kPa, 25 kgf/cm2); Deviation between cylinders 29 to 43 psi
Full service-parts list: Yanmar YDG2700EV-G6EH →
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.