Small engine valve adjustment


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Old 12-26-20, 11:08 AM
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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?
 
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Old 12-26-20, 11:26 AM
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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.
 
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Old 12-26-20, 06:52 PM
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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.
 
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Old 12-26-20, 06:59 PM
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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.
 
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Old 12-27-20, 10:41 AM
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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.
 
 

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