Valves not opening and closing properly

B

bluefitness

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4.75 HP Briggs engine


I am not getting any compression from the above referenced engine. It is used on a push lawn mower. I removed the head and manually turned the crankshaft. The valves did not open and close as they should. The weird thing is that the valves opened a closed when turning the crankshaft the wrong way (counterclockwise). Do you think it is a camshaft issue or possible a broken tappet?
 
M

Micah_repairman

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I've worked on a mower that won't get compression you'll have to get a new engine I had to replace the engine on it
 
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Rivets

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Post your entire model, type and code numbers and I will find you a service manual, if you think you have the knowledge to repair. Valve should open and close either way you turn the crank. Could be a cam problem, but I doubt it is a tappet problem.
 
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bluefitness

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Rivets said:
Post your entire model, type and code numbers and I will find you a service manual, if you think you have the knowledge to repair. Valve should open and close either way you turn the crank. Could be a cam problem, but I doubt it is a tappet problem.
Click to expand...

Thanks

Here are the numbers:

09T802-1075-B1 07120754
 
D

DaveTN

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You say when you turn it in normal direction of rotation, the valves do not operate properly, but when you rotate it counter, they do. My cousin had a rider engine brand new break a cam in two pieces. It amazingly ran but clanged and kicked like a mule in a tin stall! In your case I would suspect a broken cam that would not operate the valves due to slippage one direction, but in reverse there is enough for the cam to catch on to move the valves. Just the angle of the break I'm guessing! Either way you will have to tear into it to see.
 
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bluefitness

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briggs-stratton-camshaft-693404.jpg

I opened up the engine and the sprocket was not spinning the shaft. The metal bracket (see above) was slightly bent and there was some damage to the plastic sprocket. Is the metal bracket the only thing that holds the sprocket in place?
 
R

Rivets

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Replace the cam. The gear has let loose of the shaft. The engine is six years old and you got four more years that the average guy with that engine.
 
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