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Tom, Technician
Category: Small Engine
Satisfied Customers: 25954
Experience:  Honda Platinum Technician
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Honda OHC lawn mower engine. Valve adjustment. I did the

Resolved Question:

Honda OHC lawn mower engine. Valve adjustment. I did the exhaust valve no problem. When I went to tighten the locknut on the intake valve "screw tappet", it stripped the threads before I was near the specified torque. Ordered new screws and locknut and even the rocker arm although it appears only the screw tappet is stripped. My concern is, how did it happen? Makes no sense to me. I was just snugging up the locknut getting ready to apply the torque wrench when I felt it give. With all new parts, I don't want the same thing to happen again. Is there something special about how you tighten these? The shop manual doesn't say anything special other than hold the tappet with the special tool while tightening the locknut. I don't have the tool but just tightening the locknut worked fine on the exhaust side. Rechecked clearance and had to do again to account for the locknut changing things. Needless to say, I'm really nervous about doing this on the intake when the new parts come in. Any thoughts would be appreciated.
Submitted: 5 years ago.
Category: Small Engine
Expert:  Tom replied 5 years ago.
Over time if they were slightly loose it will damage those threads over time just normal wear and tear . It's actually very common if these were not adjusted at the proper intervals. The new parts will work just fine and you will have no issues. Hoped this helped. Positive feedback and bonuses greatly appreciated.
Customer: replied 5 years ago.
Reassuring except this is a one-season old mower. First-time adjustment with probably less than 150 hours on it. Wouldn't expect new parts like that to fail. What did I do wrong?
Expert:  Tom replied 5 years ago.
Nothing . Actually these are know to be slightly loose from the factory and the normal vibration damages the threads. You did not do nothing wrong and the new parts will install fine and no issues.
Customer: replied 5 years ago.
Now I'm not reassured. Guess I'll just have to see what happens when the parts come in. If it strips again, order more parts. I went with the manual's 5.8 ft-lbs of torque which is very little and doesn't seem like it should strip the threads, even with the small "screw" size. Actually I used an in-lb wrench at 70 in-lbs. Should be accurate. I guess I'm done unless you have any further thoughts.
Expert:  Tom replied 5 years ago.
No it's just a factory defect and you should be fine you did everything correctly . Hoped this helped. Positive feedback and bonuses greatly appreciated.
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