Kohler PCH680 / PCH740 — Crankcase Vacuum Test
Testing & diagnosis
For the Kohler PCH680 / PCH740, from the Kohler service manual.
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Before you start
- Carbon Monoxide can cause severe nausea, fainting or death. Only operate in well ventilated areas.
Procedure
- Insert rubber stopper into oil fill hole. Be sure pinch clamp is installed on hose and use tapered adapters to connect hose between stopper and one manometer tube. Leave other tube open to atmosphere.
- Start engine and run no-load high speed.
- Open clamp and note water level in tube.
- Level in engine side should be a minimum of 10.2 cm (4 in.) above level in open side.
- Close pinch clamp before stopping engine.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Crankcase vacuum minimum 10.2 cm (4 in.) of water
Source: Kohler 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.