QuestionMy mother ( 84 ) years old ) has a MTD/Yard Machine garden tractor with a 18 hp Twin/ L head B&S motor that has a compression release problem. The valves are not adjustable on this motor . Can you instruct me how to perform this task. I am not a mechanic but I am sure I can perform the repairs with some instruction.I live a couple hours away from her but I hope to get there in the near future. My brother is also helping me.
Thank you
Randy
AnswerHello Randy:
>>The Following is a Basic Instruction File for Setting the Valve Clearances on Non OHV Engines. If you Provided me with the Correct Make and Model of the Engine then the Specifications are Included. If Not I May be Able to Provide the Specifications if you Supply me the Make and Model Numbers.
>>The Most Common Clearances are Listed for this Engine in the Following File. Thanks. Any Input is Appreciated.
>>On this Model Engine I Usually Suggest Reseating the Valves if the Valve Clearance Requires Adjusting.
>>**Remove the Carburetor and the Crankcase Breather/Vent and the Valve (Stem) Cover so you have Access to the Valve Stems, Springs and Keepers.
>>Set 1 Cylinder (on Twin Cylinder Engines) to TDC on the Compression Stroke. Using a Blade Style Feeler Gauge, Check the Clearances. The Intake should be .005in - .007in and Exhaust .008in - .010in. If the Feeler Gauge will Not Slide Between the Valve Tip and the Tappet, then you Must Reset the Clearances.
>>**You Will Require a Small Engine Valve Spring Compressor to Remove the Springs and Keepers from the Valve Stems.** Some Engines Use a Valve Keeper that is like Automotive Keepers (2 Cone Shaped Keepers that Set in the Valve Retainer/Rotocoil Assembly)and the Other Style is a Slotted Retainer that is Moved (once the Valve Spring is Compressed) to the Larger Opening in the Retainer and the Retainer Slips Over the Valve Stem Tip for the Valve to be Removed. The Valve Spring Compressor Tool Cost Approximately $30 to $40us. You should also Purchase a Valve Lapping Tool ($15 to $20us) to Lap/Seat the Valves.
>>Remove the Head/s.
>>Set 1 Cylinder so the Piston is at TDC on the Compression Stroke And Check the Clearances Between the Valve Stem Tip and the Tappet. The Clearances are as Follows: Intake Valve Clearance is .005in - .007in and the Exhaust is .008in - .010in.
>>You have to Lightly Grind the Valve Stem Tip and Place the Valve Back Into the Engine (you can Hold the Valve Seated by Hand) and Check the Clearance Until you Reach the Required Clearances.
>>**++** For this Engine Model I Suggest you Reseat the Valves while you are Setting the Correct Valve Clearance. For this you will Need a Small Valve Seat Suction Tool. This can Usually be Purchased for $10.00us and has a Suction Cup that Hold the Valve Head so you can Turn the Valve Back and Forth and Dress up the Valve Seat. Valve Grinding Compound is Approximately $5.00us a Tube and a Tube Last the Shop About a Year. It Doesn't Take a Lot to Reseat 1 Engine.**++**
>> Once the Valve Clearances are Reached and the Valve Seat is Nice and Dull; Re-Install the Valves on that Cylinder and Turn the Other Cylinder to TDC on the Compression Stroke and Set that Cylinders Valve Clearances.
>>Once that Cylinder is Set, then Assemble the Engine.**
>>This Web Page; http://www.affordablegokarts.com/va
lve-lapping.php has a Fairly Good Description and Instructions on Valve Lapping and a Good Explanation of what to Look for when Seating the Valves.
>>You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.outdoordistributors.com/parts.html and Select the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Select the File #42 . Then Select the Folder #422700. **Note: you can Download and Save the Breakdown for your Engine by Selecting the 2nd Icon from the Left at the Top of the PDF page.**
>>If you Hit a Snag, have More Questions or this Does Not Correct the Problem, I Hope to be Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 3 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Follow Up Questions are Received Anytime. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
