Small Engines (Lawn Mowers, etc.): knock and bad vibration, briggs and stratton, cylinder compression

Question
QUESTION: John I asked you a question on April 4th about a knock in my 19.5HP Briggs engine. Mod# 351777.I forgot to mention the bad vibration at low idle. i took off the pulleys hoping to find a bent one.The vibration is still there. Any thoughts on the vibration? Thanks Dean
ANSWER: Hello Again Dean:

Is the Vibration with or without the Blades Engaged? Check the Cylinder Compression. Improper Compression on 1 Cylinder and Good Compression on the Other will Cause a Vibration. Send me the Model Numbers Off the Mower, Please. You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.outdoordistributors.com/ and Select the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Select the File #35. Then Select the Folder #351700. Hope this Helps. I am Here if You Require More Assistance. Let Me Know What Happens, Please. Thanks.

Good Luck

Respectfully  

John

---------- FOLLOW-UP ----------

QUESTION: John thanks for the help. I was able to check the pistons,and one of them is not moving. I took the engine from the tractor and have it on my bench.I took the crankcase bolts out hoping to drop the bottom half to see in anything was bad. I can not get the bottom all the way off.does the engine have to be disassembled from the top down? I can see the connecting rod in about 3 pieces inside the housing.Should the bottom half of the crankcase come off without taking anything loose from the inside? Engine model # 351777-1036-A1. Mower Mod# 917.258662 Thanks Dean

Answer
Hello Again Dean:

Slide the Oil Pan Back Into Place. Use 440 Grit Sand Paper and Clean the Crankshaft of any and All Rust. The Fit Through the Oil Pan is Close and a Small Amount of Rust on the Crankshaft will make the Oil Pan Removal Very Difficult. Hope this Helps. I am Here if You Require More Assistance. Let Me Know What Happens, Please. Thanks.

Good Luck

Respectfully  

John