Small Engines (Lawn Mowers, etc.): Craftsman mower wont turn over, briggs stratton, internal passages

Question
Hi John,

First off I want to thank you for the time and energy you put into answering the many questions you get, your dedication is very much appreciated.

I have a 19.5 HP Briggs & Stratton craftsman mower (engine model 42e707. The mower has sat in the garage for around 2 years without being used (I know, a big mistake). I wanted to get it up and going this summer. I have replaced the spark plugs, changed the oil, and put in a new battery. The engine was not turning over, so I checked the solenoid and found it to be working fine. I found the starter was not working. So I bought a new starter and put it on. When I went to start it up, the starter was not able to turn over the motor. I tried spinning the flywheel by hand and found it to be very hard to spin. I took the two spark plugs out and found that the flywheel spun fairly easy by hand, I then tried to start the mower with the plugs out. The starter was able to spin the flywheel with the plugs out. What can be causing the binding that won’t let the flywheel turn? I am fairly novice at motor repair mind you. I have been turning the flywheel manually and it seems to be slowly loosening up. The starter still gets stuck at the point there is the most resistance. I think the point of most resistance is the compression stroke. but I may be wrong. Any help would be greatly appreciated.

-Ryan  

Answer
Hello Ryan:

Thanks for the Good Words. Usually when an Engine Sets this Long you will Need to do the Following; 1- Remove All Belts from the Engine Drive Pulley. 2- Remove, Soak and Clean the Carburetor. The Following is a General Instruction File for Carburetor Cleaning. Even though the Carburetor Looks Clean, the Internal Passages May be Restricted with Varnish that Gas Causes to Build Up over Time. I Suggest you Make Sure the Gas is Free Flowing to the Carburetor Inlet Port. If the Gas is Free Flowing to the Inlet Port, then  **Remove, Disassemble and Soak the Carburetor Overnight in Carburetor Cleaner (I Use Gunk). I have Found that Most People can Use a Breakdown/IPL and Disassemble the Carburetor Enough for Proper Cleaning. You Only have to Remove the Bowl (if Applicable), Float Pin (if Applicable), Float (if Applicable), Needle Valve and Needle Valve Seat if Applicable. This is a Flat O-Ring Located in the Inlet Port the Float Needle Rests in. Use a Strong Wire with a Slight Bend to Remove the Old Seat. Sometimes a Small Pocket Screw Driver can be Use Also. The New Seat will have a Slightly Beveled Side and a Flat Side. The Flat Side goes Towards the Carburetor Body when Inserted into the Inlet Port. Spray the Seat with Spray Lubricant to make Installation Easier. The End of a Drill Bit that is Slightly Small than the Seat can be Use as an Insertion Tool. Wear Gloves or Use a Rag when Handling the Sharpened End of the Drill Bit. Remove Any Adjustment Screws that Go Into the Carburetor Body. The Welch Plugs Do Not have to be Removed. Then Soak the Carburetor Body and Parts in a 1 Gallon Can of Gunk Carburetor Cleaner Overnight. The Can has a Parts Tray Inside it for the Small Parts. Once the Carburetor and Parts are in the Cleaner, you can Replace the Lid for Safety and to Prevent Accidental Spillage. Then Blow Out the Passages with Compressed Air.*** (Do Not Use High Pressure Air for the Zama Carburetors, they have Check Valves for the Primer and these are Usually Blown Out of the Carburetor if Not Careful. Allow the Zama Carburetor to Set on a Drip Pan and Dry)***. ****All the Carburetor Adjustments are the Same for Lawn Mower and Trimmers. There are Several Location for the Air Mixture Screws. The Idle Air Mixture Screws are Usually Located at the Top of the Carburetor Bowl and the Top of the Carburetor Body. If the Main Air and Idle Air Mixture Screws are Side by Side on the Side of the Carburetor, then the Idle Air is the Farthest from the Engine. The Main Jet Air Mixture Screw is Located in the Bottom of the Carburetor Bowl or Beside the Idle Air Screw on the Side of the Carburetor Body. Some of the Older Model Carburetors have the Main Jet Mixture Screw Straight in from the Top of the Carburetor Body (this is Rare anymore). If you have Cleaned the Carburetor (Disassembled and Soaked Overnight in Carburetor Cleaner (I Use Gunk). Then Blow Out the Passages with Compressed Air and Install a New Kit if Required. Now Setting the Air Mixture Screws:  ****Turn the Idle Air and Main Air Mixture Screws In Until SNUG **Do Not Jam** Then Reverse Both Screws 1 1/2 Turns. Holding the Throttle Full Open, Start the Engine. Turn the Main Air Mixture Screw Clockwise Until Proper Revs are Obtained. Occasionally you May have to Turn this Counter Clockwise to Achieve the Proper Revs. Now Allow the Engine to Idle. Set the Engine Idle Screw (Not Idle Air) so the Engine will Stay Running if Required. Now Set the Idle Air Mixture Screw so there is No Hesitation when Throttling from Idle to Full Throttle. Reset the Engine Idle if Required.**** If This Carburetor has a Single Air Adjustment. Use the Section Above that Pertains to Full Throttle RPM Air Mixture Screw and then Adjust the Screw if Required to Eliminate Any Hesitation when Throttling from Idle to Full Throttle. This file was Intended to Give you the Basic Carburetor and May Not Reflect Yours. If you have Questions, Please Ask. 3- Put a Small Amount of Marvel Mystery Oil into th Cylinder/s and Turn the Engine with the Plug/s Out. It May take Several Times of Adding the Marvel Mystery Oil and Turning the Engine Over with the Plugs Out to Properly Loosen the Rings and Piston/s in the Cylinder/s. 4- Change the Oil. The Crankcase Oil May be Contaminated with Gas. 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 # 42. Then Select the Folder # 42E700. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 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. Thanks.

Respectfully

John