QuestionQUESTION: I have a 24 HP OHV B&S motor on my riding mower, engine code YBSXS.4242VF. My problem began last time I was using it, it started idling way up, then way down, changing from one to the other very fast. If I engage the blade, the motor shuts off entirely. A while back (while still under warranty), it was doing this exact same thing. Craftsman's customer service told me to check the safety switch under the seat, I cleaned it out and it has worked ever since. I just cleaned the switch, still does it. I even took a piece of wire and jumped the terminals in the switch, still does it. What are my options for troubleshooting where the problem lies? (and can I bypass all this safety stuff that keeps me from using my mower? I'll be careful I promise.)
Thanks,
Lee
ANSWER: Hello Lee:
Usually the Problem you Described is Caused by a Restricted Carburetor Jet. I Suggest you **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) and Needle Valve and 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. Install New Parts if Required.** **PLEASE REMEMBER THAT THE INSTRUCTIONS FOR CHECKING THE SAFETY SWITCHES IS JUST THAT!!! FOR CHECKING ONLY. I NEVER Suggest a Mower be Operated with a Safety Device or Switch Disconnected or Bypassed. Now. On Some Model Mowers you can Simply Unplug the Safety Switch from the Harness. On Other Models you have to Place a Jumper Wire Between the Harness Terminals (on the 4 Post Switch Jumper from Same Color Wire to Same Color Wire). Check the Clutch/Break and the Blade/PTO Safety Switches First. Check the Seat Safety Last. Usually the Seat Safety is Not in the System for Starting the Engine. Just to Ensure Someone is in the Seat when Engaging the Transaxle and/or Blades.** You can View a Breakdown/IPL of the Engine at this Site Addy; http://www.briggsandstratton.com/maint_repair/manual_and_more/doclist.aspx?categ and Enter the Model Numbers (XXXXXX) and Type Numbers (XXXX) in the Appropriate Boxes and Click GO. Then Select Download PDF. To View a Breakdown of this Unit Go to this Site Addy, http://www.searspartsdirect.com/partsdirect/index.action and Enter the Model Numbers and Click Search. From this Page you can View Diagrams and Parts Lists for you Equipment Using the "View Sub Components" Section. 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
---------- FOLLOW-UP ----------
QUESTION: Greetings John!
Well, it's been quite an adventure. Per your suggestion, I removed the carb to soak in the solution overnight. I went ahead and tore it down to the base parts and ordered a complete rebuild kit, fuel lines and o-rings for the manifold. After the carb was removed I noticed the vacuum line from the fuel pump to the valve cover had a split in it, so I replaced it while I was at it. I just put everything back together today, and still cannot cut my grass.
Now I have a new symptom. It idles very low, and the throttle has no response whatsoever on the engine speed. I set the brake and rigged the switch under the seat so that I could inspect the engine while it runs. I think the governor either needs to be adjusted or is busted.
If I take the governor arm that is attached to the throttle linkage and wiggle it up and down it has an effect on the idle of the motor. If I manipulate it just right, jiggling it up and down in time, the governor kicks in (I'm guessing) because the arm moves of its own accord and the engine starts purring like a kitten (Note - removing the air filter and using my hand to cut off the air supply, then letting off and manipulating that caused it to do the same thing).
Once I have convinced it to run this way, the engine and throttle response are fine. Everything works exactly like it's supposed to until I let off the brake or engage the blades. Either one kills the engine unless I immediately reverse my action and it will go back to the low idle with no throttle response. I can go through the same action, and it will run right again, until I put a load on the engine and it reverts to its problemed state.
I've been reading up on how governors work, and tried to adjust it by loosening the nut on the carriage bolt, but I did not know which way I would need to turn the governor shaft itself. So I turned it one way, and everything seemed fine. Until I put a load on the engine that is.
What can I do to adjust it, and what are the chances I won't have to have the case split open to fix this? (And how big of a job is that compared to rebuilding the carb? Time for a service shop?) For now I am going to borrow my neighbor's mower, to get the job done until I can get mine up and running again.
Thanks John,
And may the Almight bless you and yours as well.
You are certainly a blessing to us!
Lee
AnswerHello Again Lee:
The Following is an Instruction File I Made for Making this Adjustment. Any Input is Appreciated. If you Removed/Loosened the Governor Arm to Remove the Carburetor, then Reset the Governor. **To Reset the Governor; Loosen the Governor Arm Bolt and Turn the Governor Shaft Clockwise Until it Stops. Using the Governor Arm Hold the Carburetor to Full Throttle. Now with the Shaft Full Clockwise and the Governor Arm and Carburetor Held at Full Throttle, Tighten the Governor Arm Bolt. If the Engine Still Runs Full Throttle, then Reverse the Rotation of the Governor Shaft, but Still Hold the Carburetor at Full Throttle with the Governor Arm. If it Still Runs at Full Throttle, then Check the Internal Governor.** There is a Safety Switch or a Safety Switch Interlock Relay that is Causing the Problem with the Engine Quitting when you Engage the Blades or try to Move the Mower Using the Transaxle. The Seat Switch or the Interlock Switch is Usually the cause for this. The Following is the Instruction File for Checking the Seat Safety Switch. **Check the Seat Safety Switch. PLEASE REMEMBER THAT THE INSTRUCTIONS FOR CHECKING THE SAFETY SWITCHES IS JUST THAT!!! FOR CHECKING ONLY. I NEVER Suggest a Mower be Operated with a Safety Device or Switch Disconnected or Bypassed. Now. On Some Model Mowers you can Simply Unplug the Safety Switch from the Harness. On Other Models you have to Place a Jumper Wire Between the Harness Terminals (on the 4 Post Switch Jumper from Same Color Wire to Same Color Wire). The Seat Safety is Showing No One is Seating in the Seat when the Clutch or Blades are Engaged.** The Following is an Instruction File I made for making this Repair. Any Input is Appreciated. This is a Simple Process. Drain the Oil and Remove the Engine to the Work Bench with the Oil Pan Facing Up. I have a Wooden Rest that was Especially Made to Hold the Engine when in this Position. Using Fine Sand Paper, Remove ALL the Rust and Debris from the Crankshaft. Remove the Oil Pan Bolts. After All the Oil Pan Bolts are Removed; Tap Lightly on the Sides of the Oil Pan to Loosen it from the Dowel Pins. When the Oil Pan is Removed, you can See the Governor Resting on Top of the Cam Gear. Lift Off and Replace with a New Governor. Check the Engine Block for Debris from the Old Governor and Wipe the Inside of the Block With a Rag, Until Clean. Set the Governor So it is Resting on the Governor Shaft and Carefully Replace the Oil Pan. Remember to Replace the Oil Pan Gasket. If the Crankshaft Seal Was Not Leaking, then Leave it Alone. It Should be OK. You can Easily Replace it While Mounted on the Machine if Required Later. Make Sure the Governor Stays in Contact with the Governor Shaft while Replacing the Oil Pan. Re - Mount the Engine to the Machine. Refill With Oil. These Instructions are Basic. Your Internal Governor May Differ. 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
