Small Engines (Lawn Mowers, etc.): bent pushrod, cylinder head gasket, gasket set

Question
I have a 2yr.old craftsman rider, model# 917.275683, it started to spit, sputter and backfire, I found the aluminum pushrod bent and the steel pushrod gone. Why would this happen? Do I need to remove the motor to retreive the rod out of the oil pan? How do I stall the pushrods correctly so this doesn't happen again. Thank you very much for your time and help.

Answer
Hello Robert:

Questioner:   Robert
Category:  Small Engines (Lawn Mowers, etc.)
Private:  No     View Published Answer
 
Subject:  pushrods
Question:  I have a 2yr.old craftsman rider, model# 917.275683, it started to spit, sputter and backfire, I found the aluminum pushrod bent and the steel pushrod gone. Why would this happen? Do I need to remove the motor to retreive the rod out of the oil pan? How do I stall the pushrods correctly so this doesn't happen again. Thank you very much for your time and help.

 
Answer:  Hello Robert:

You Really Need to Locate the Missing Push Tube. If it is Inside the Crankcase, then you have Another Problem and Replacing the Push Tubes is Not Going to Help You Get this Engine Running. You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.smallenginepartswarehouse.com/parts.asp and Select the Shop Online Parts Look Up. Then Select the Model Tab. Then Select the OEM and Enter the Model Numbers. Then Double Click on the Model in the Results Area. Now you can Select the Section of the Engine you Wish to View. Select Cylinder Head, Gasket Set-Valve, Valves. The Push Tubes Are Moved by the Tappets (Breakdown/IPL #45). There is No Way the Push Tube can Get Into the Crankcase Unless the Cam Breaks and the Tappet is Allowed to Fall Into the Crankcase. From your Description, I Suggest you Locate the Push Tube. Remove the Oil Pan if the Tube Can Not Be Located Without Doing So. It is Better to be Safe than Sorry. When you Replace the Push Tubes, Use Red (High Temperature) Thread Lock on the Adjuster Locks and Be Sure the Adjuster Locks Are Tight. I Do Not Use the Setting Called for by the OEMs. I have Found that the Following Works Best. Remove the Valve Cover (on the Dead Cylinder for Twin Cylinder Engines). Set the Cylinder you are Setting the Valves on to Top Dead Center When Setting the Valve Clearance. Now Loosen the Valve Adjuster Locks and Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .008in - .010in. I have had Better Performance Out of the Mowers and Less Burnt Valves Using these Settings. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John