QuestionQUESTION: LS1000 42" deck,OHV 17.5 briggs. Model# 917.272673 not sure if you need the mode, type, and code off the top of the muffler, but here u go. 51c707, 0230e1, 731ze. I dont know if there numbers on the engine u need, but if so, just let me know, and know where to look. I've had this mower for almost 4 years, and over the last year or so, i've put on 3 starters, and 2 solenoids, new battery, new starter, and it started fine for bout' a week, then went back to dragging when you turn it over. It's like it turns 3/4 of the way around then stops, like there is too much compression of something. I've got a new starter on it now, and kniw if I just continue to hold the key over it will continue to burn up the starters. From google i've seen something about the vavles may need adjusted???? If so perhaps you may know the specs as to where they should be. Thank yoy for any help, and for this service you all provide. My email is
ANSWER: Hello Tim Smith:
>>You are Correct in Thinking the Valve Clearances are Incorrect and Require Setting.
>>When the Valve Clearances become Slight Off, the Compression Release cannot Operate as Designed and you have the Problem you Described.
>>According to the Manual, this Unit has a 31C707-0230-1 Model Briggs Engine.
>>The Following is a Basic File I made for Setting the Valve Clearances. Any Input is Appreciated.
>>**I Do Not Use the Setting Called for by the OEMs. I have Found that the Following Works Best.
>>Remove the Valve Cover (on the Dead Cylinder for Twin Cylinder Engines).
>>Check the Push Tubes and make Sure they are Not Bent.
>>Set the Cylinder you are Setting the Valves on to Top Dead Center on the Compression Stroke When Setting the Valve Clearance. Now Loosen the Valve Adjuster Lock and Using a Blade Style Feeler Gauge, Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .006in - .008in. Loosen and Tighten the Rocker Arm and the Feeler Gauge is Placed Between the Rocker Arm and the Valve Top where the Rocker Arm Pushes on the Valve.
>>***BE SURE TO TIGHTEN THE ADJUSTER LOCK AFTER YOU HAVE THE PROPER VALVE CLEARANCE***
>>If you Remove the Valve Cover and then Turn the Engine by Hand, you can Watch the Intake Valve Movement. When the Intake Valve Closes, the Piston will Just Starting the Compression/Power Stroke. >>Position the Piston so it is Completely at the Top of the Cylinder and then Set the Valve Clearances.
>>Be Careful and Don't Jam the Wire in the Cylinder. Usually the Piston will Push the Wire Out of the Spark Plug Hole with No Problems.
>>To View a Breakdown of this Unit Go to this Site Addy, http://www.searspartsdirect.com/partsdirect/index.action?sid=PSHx20080114x00001 and Enter the Model Numbers and Click Search. >>From this Page you can View Diagrams and Parts Lists.
>>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. 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. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: Thanks for the great help. The tip vavle was all the was out to .025, and the bottom one was .016. It rans like a new one. Except one little things which isn't a big deal, but when I shut it off, if backfires still.it was doing this before aswell, and i'm not to concerned. How often will I need to keep an eye on this, every season? Why does this model engine vavles continue to need adjusted? Motor defect, guaranteed customer service, regular engine wear? My dad has a craftsman mower, cept it has a 15 hp kohler, he's never turned a bolt on it in 6 yrs. Thanks again, and if I could ever return the help, come visit me at www.majorgeeks.com theres a great forum, with tons a free DL's. Thanks again
AnswerHello Again Tim:
>>I am Glad I was able to Assist you in Solving this Problem.
>>For some Reason some of the OHV Engine have to have the Valve Clearances Reset every 100 to 125 Hours of Running Time or Less.
>>I have Asked All the OEM's about this Problem and have gotten the Same Answer. They have No Answer to my Question. lol.
>>I have Found that Using the Blue Thread Lock on the Adjuster Helps Prevent this Problem, but it makes it Harder to Adjust the Valves when they Do Wear under Normal Operation.
>>As for the Backfiring, Does this Engines Carburetor have a Solenoid Mounted On it?
>>If Yes, then the Solenoid is Bad.
>>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.**
>>The Newer Engines Usually have a Carbureotr Anti-Backfire Solenoid to Shut Off the Gas Flow to the Main Carburetor Jet to Prevent the Backfire Problems that the Newer Engine have Due to the Close Valve Clearances.
>>The Older Engines had a Much Larger Valve Clearance and there was Rarely any Engine Backfire.
>>Return the Engine to Idle and Allow it to Idle for 2 to 3 Minutes before you Shut Down the Engine and this will Usually Prevent the Backfire Problem.
>>I have you Site Addy and will Visit in the Next Few Days.
>>Thanks for the Ratings and Comments.
>>Till Next Time. May All Your Mechanical Problems be SMALL ONES and as Always, May the All Mighty Bless You and Yours. Be Safe and Happy.
Best Wishes and Good Luck
Respectfully
jbridger (John)
