Generac — Compression Test
Testing & diagnosis · Engine
From a Generac service manual covering: 10 KVA, 13 kVA, 8 kVA. Check it applies to your exact model before use.
Applies to: Generac EcoGen 6 kW, Generac GH-410 engine, Generac GH-426 engine, Generac GT-530 engine, Generac GT-530 engine, Generac GT-999 engine, Generac OHVI engine
Procedure
- Shut off fuel supply.
- Remove both spark plugs.
- Ground spark plug boot or Wire 18.
- Open throttle wide open.
- Insert compression gauge.
- Crank engine until pressure stabilizes.
- Record highest reading.
- Repeat for other cylinder.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Minimum compression typically 150 PSI cold
- Difference between cylinders <25%
Full service-parts list: Generac EcoGen 6 kW →
Source: Generac 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.