Small Engines (Lawn Mowers, etc.): 6.5 hp B&S starts fine wont stay running, stratton family, briggs stratton


Question
Craftsman tiller model# 917.294482 6.5hp intek Briggs & Stratton Family 4BSXS.2051HF 275821

Tiller starts great in choke position and will run for a while but when you move choke lever to run it doesn't run smoothly it almost sounds like its missing or the choke is still engaged, like a sputtering sound. Then when you engage tiller it tills for a few seconds then shuts down but will start right back up in choke position. Tiller will actually till for a while when you leave the choke lever in the 3/4 open position but will eventually shut down and never runs smoothly.

I suspect a carburetor problem, I removed carb and gas tank made sure gas was flowing freely from tank to carb and that the line was free and clear, tank is also clean with fresh gas. Removed carb and removed bowl, float and needle valve and sprayed carb cleaner through all ports, and thoroughly cleaned it out making sure carb cleaner flowed through all ports freely. gaskets looked like they were in decent condition also. This carburator has no adjustment screws just an idle set screw on the butterfly.

Do they make a carb kit for this? could this be my problem? Any other input would be greatly appreciated thanks in advance.

Answer
Hello Rick:

>>From your Description it Sounds like the Carburetor does Require Soaking and Cleaning, the Head Gasket may be Bad and Require Replacing or the Head Bolts may be Loose and Require Torquing.
>>I Suggest you Soak and Clean the Carburetor First.
>>Even though the Carburetor Looks Clean, the Internal Passages May be Restricted with Varnish that Gas Causes to Build Up over Time. Spray Cleaners Remove this Varnish in Layers, so Soaking is the Only Sure Way to Remove ALL this Varnish from the Carburetor and Ensure the Carburetor is Operating Correctly.  
>>You can View a Breakdown/IPL of the Engine at this Site Addy; http://www.briggsandstratton.com/maint_repair/manual_and_more/ and Enter the Model Numbers (XXXXXX) and the Type Numbers (XXXX-XX) in the Appropriate Boxes and Click GO. Then Select Download PDF.
>>Spray Carburetor Cleaners do Not Usually Clean a Small Engine Carburetor.
>>The Following is a Basic File I Made for Cleaning Carburetors. Any Input is Appreciated. Even though the Carburetor Looks Clean, the Internal Passages May be Restricted with Varnish that Gas Causes to Build Up over Time.
>>Spray Cleaners Remove this Varnish in Layers, so Soaking is the Only Sure Way to Remove ALL this Varnish.  
>>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.
Remove Any Adjustment Screws that Go Into the Carburetor Body. The Welch Plugs Do Not have to be Removed.
>>If you are Able to Remove and Disassemble the Carburetor and Keep the Gaskets Intact, then Usually these Gaskets can be Reused. The Only Parts you May Need to Replace is the Needle Valve.
>>The Float Needle Usually is Not Replaced Unless it is Not Operating Properly (the gas flow not shutting off and the carburetor is Flooding). Do Not Remove the Main Nozzle. This is a Pressed Fit and Removal is Not Required for Cleaning. Soaking and Blowing the Carburetor Out After Soaking will Clean the Nozzle.
>>Once Disassembled, 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 Nearest 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 (Except Tank Mounted 9200 and 100900 Engine Model Carburetors), 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.
>>For the 9200 Model Tank Mounted Carburetor Adjust the Air Mixture Screw Full In, then Reverse 1 1/2 Turns. Set the Throttle Lever to Full Throttle and Start the Engine.
>>Now Carefully Use 1 Finger and Open the Throttle Plate and Over Rev the Engine Slightly. If the Engine Over Revs and Does Not Struggle to Over Rev, then the Carburetor is Set. If the Engine Struggles to Over Rev, then Turn the Adjustment Screw In 1/4 Turn and Repeat the Over Rev Test.
>>If you Adjust to 1/2 Turns In and the Engine Still Struggles to Over Rev, then Return the Adjustment Screw to 1 1/2 Turns Out from Snug and Turn the Screw Out 1/4 Turn. Do the Over Rev Test. Continue this Process Until you have the Engine Over Revving without Struggle.
>>By Adjusting the Carburetor on this Style Carburetor Until the Engine Over Revs without Struggle, you have Adjusted the Air Mixture to the Best Possible Setting.
>>This file was Intended to Give you the Basic Carburetor Cleaning Instructions and May Not Reflect Your Carburetor Components.
>>If you have Questions, Please Ask. The links above Provide Good Directions on Cleaning the Carburetor.  Make sure you use an Compressed Air to Blow through all the Carburetor Passages to make sure they are Clear.  
>>1- http://www.repairfaq.org/samnew/lmfaq/lmclctc.htm   
>>2- http://www.cpdonline.com/692509.pdf   .
>>You can Locate the Correct Specification (Bolt Torque, Valve Clearances, ect) for this Engine at this Site Addy; http://outdoorpowerinfo.com/engine_specs/ and Select your Engines OEM and the Specification Chart you Require.
>>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. 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