Intake Valve Not Fully Opening.

[Coby]

Hello, everyone.

I have a Craftsman with a Briggs Flathead engine Model 42E707. One of the intake valves is not fully opening. The valve is new and moves freely. The problem seems to be the valve lifter. When the valve is taken out, the tappet is loose and can be moved easily. When the valve is installed, the lifter only opens the valve by approximately 1/4". The other three valves are all working fine.

I am a novice with engines, so apologies if I am not explaining very well. I was wondering if it is a problem with the Tappet or a problem with the camshaft lobe. I appreciate any advice or opinions.

Ron

 

[ILENGINE]

Normally one valve not opening as far as the other is a worn camshaft lobe. unless there is excessive play in the valve to tappet distance which I don't suspect in this case.

 

[Coby]

Thank you for such a fast reply. I appreciate your help.

 

[Hammermechanicman]

You will probably have to pull the engine apart and see if you have a worn down cam lobe of broken tappet.