Small engine valve adjustment

Old 12-26-20, 11:08 AM
Thread Starter
Join Date: Jan 2015
Location: USA
Posts: 915
Received 86 Upvotes on 76 Posts
Small engine valve adjustment

I have numerous pieces of equipment with small engines (2 and 4 stroke) and have owned some for many years. I happened to notice a leaf blower maintenance schedule included checking / adjusting valves annually. This is not something I've ever done with any small engine as a maintenance item. Should valves be adjusted or at least checked periodically, irrespective of an issue or is this something to be left alone until a problem develops, perhaps tapping? If checking is advised what's the frequency?
Old 12-26-20, 11:26 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,592
Received 1,708 Upvotes on 1,525 Posts
Ideally you would periodically check the valves according to the owners manual. Unfortunately I'm a bit lazy and don't really do it. I will do at least the first valve inspection per the manual with expensive equipment but I'm less responsible with less expensive machines as I tend to wait for some indication of trouble.
Old 12-26-20, 06:52 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 18,015
Received 109 Upvotes on 99 Posts
Overhead valve engines with solid lifters need the valves checked and adjusted as part of periodic maintenance. Excessive clearance can result in broken rocker arms and ruined cam shafts. The procedure and specs varies according to the manufacturer and model of the engine.
Old 12-26-20, 06:59 PM
Join Date: Jan 2011
Location: USA
Posts: 5,006
Received 125 Upvotes on 110 Posts
I've owned a lawn care business for the last 10 years and also own no less then 10 gas powered tools and have only once had the valves adjusted on a POS John Deere Z Turn that was giving me trouble starting.
Old 12-27-20, 10:41 AM
Join Date: Oct 2015
Location: Ct.,USA
Posts: 2,878
Received 227 Upvotes on 201 Posts
Usually only 4-cycle engines with overhead valves have the capability to adjust the gap between the valve stem and the lifter. With valve in block engines, the valve gap can become greater or less, depending on what wears and involves much specialized tooling to correct. It is not a DIY item. 2-cycle engines don't have mechanical valves.

Thread Tools
Search this Thread
Ask a Question
Question Title: