QuestionBriggs 402707, 1205 01. Engine starts and runs fine for about 45 min. then begins to surge and run rough. Could not get any response from turning mixture screw. I removed carb, soaked, and installed carb kit. Engine ran great first time out. Second time out after 45 min of mowing engine was surging again and running rough. What should I check next? Many thanks.
AnswerHello Bill:
>>The Following is a Basic Instruction File I made for this. Any Input is Appreciated. I Usually Suggest you Check the Following in this Order for a Problem like yours.
>>1- Check the Gas Tank Cap and Ensure it is Venting the Tank. A Vacuum Builds in the Tank and the Gas Flow Stops or Slows (15 to 45 Minutes and if the Small Granular Sand is in the Tank it can Take Several Days of Constant Running to Bring All the Sand Particles to the Tank Outlet Port) to a Point it Shuts Off the Engine.
>>2- Replace All the Spring Style Hose Clamps with Screw Style Hose Clamps on the Fuel System.
>>3- Check the Carburetor Solenoid.
>>Sometimes the Plunger is Moving, Just Not Far Enough to Allow the Gas to Enter the Jets or it is Overheating and Leaning Out the Fuel to the Engine.
>>The Following is a Basic Instruction File I made for Checking the Carburetor Solenoid. Any Input is Appreciated.
>>**Check for Current/Voltage (10.5 VDC Minimum) to the Carburetor Shut Off Solenoid. If the Carburetor Shut Off Solenoid has Current, then On Some Solenoids you can Remove the Needle and Replace the Solenoid to Test them.
>>****PLEASE DO NOT OPERATE THE MOWER WITH THE SOLENOID BYPASSED IN THIS MANNER. THIS IS "ONLY" FOR TESTING.****
>>For Others, Remove the Carburetor Solenoid and Go to the Hardware Store. Purchase a Bolt of the Same Diameter and Threads. It Needs to be 1/2" to 3/4" Long for the Horizontal Mount Solenoids and 1/4" to 1/2" Long for the Vertical Mount Solenoids. Put this Bolt in Place of the Solenoid. If this Corrects the Engine Problem, then Replace the Solenoid.
>>***NOTE: THIS IS FOR CHECKING THE SOLENOID ONLY I NEVER SUGGEST YOU OPERATE THE ENGINE WITH THE SOLENOID OUT OF THE CARBURETOR EXCEPT FOR TESTING PURPOSES***
>>Sometimes the Plunger is Moving, Just Not Far Enough to Allow the Gas to Enter the Jet Properly.** **Use 440 Wet Dry Sand Paper and Engine Oil to Clean the Pin. Wet the Sand Paper with Oil Until it is Flexible and then Lightly Polish the Pin. There is Some Slop/Free Play in the Solenoid Pin. Usually the Electromagnet is Simply Not Pulling the Pin as it Should or there is a Small Bur on the Pin. Use 440 Wet Dry Sand Paper and Engine Oil to Clean the Pin. Wet the Sand Paper with Oil Until it is Flexible and then Lightly Polish the Pin. Clean and Lightly Oil the Pin before Inserting it Back into the Solenoid. Just a Film of Oil is All it Takes.**
>>4- Operate the Equipment Until it Starts Surging or Quits (15min to 1hr). Then Immediately Check for Fire from the Plug. If the Plug is Firing, then
>>5- Depending on the Model Mower, it can Also be the Pickup Tube in the Gas Tank.
>>If No Fire, then Remove the Shut Off Wire from the Coil and Check for Fire.
>>If Still No Fire, then the Ign Module or Coil is Bad. **Even if the Coil is New or Fairly New, it can Still be Bad.** On JD Mowers; Remove the Igniter/Module and the Coil and have the Local JD Dealer Test them.
>>Usually on JD Mowers the Igniter is the Most Common cause for No Fire to the Plug.
>>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 #40 . Then Select the Folder #402700. **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 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.
>>I Hope You and Yours had a Happy Holiday Weekend and May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 5 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. Comments and Ratings are
Greatly Appreciated. Thanks.
Respectfully
John
