Kohler — Automatic Compression Release (ACR) Check
Testing & diagnosis · ACR mechanism
From a Kohler service manual covering: K141, K161, K181, K241, K301, K321, K341, K91. Check it applies to your exact model before use.
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Before you start
- Do not attempt to bend hardened steel ACR tabs; they will break.
Procedure
- Check valve-to-tappet clearances and adjust to specification.
- Remove cylinder head and turn engine over by hand to BDC of intake stroke.
- Mount dial indicator on top of exhaust valve and set at 0.
- Slowly turn flywheel clockwise and watch dial indicator.
- When piston is about 2/3 of way up cylinder, exhaust valve should open .031-.042 in.
- If valve lift is not within range, adjust ACR tab.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Exhaust valve opening .031-.042 in.
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.