QuestionQUESTION: This motor was oil starved. I pulled it apart and I was able to save the crank, however replaced the rod and counterweight. Everything turns freely and seems to operate as it should.
Upon attempting to line up the crank/cam, I noticed that the dots will not line up exactly. It's a tooth off either way....very odd I thought.
So I buttoned it up, adjusted the valves per B&S specs and tried to start it. It immediately backfired through the carb, and then just cranks. If I play with the choke/throttle, it will occasionally backfire, but still nothing.
So what did I do wrong. I think it may be the valve adjustment, but that cam alignment is bugging be too. Any information or ideas would be greatly appreciated. Thanks!
ANSWER: Hello Jason:
The Timing Mark (-) on the Crankshaft Gear is Usually on a Tooth of the Gear and the Cam Mark (.) is Located Between the Teeth of the Cam Gear. There is No Way the Timing Marks will Not Line Up. You May have Used the Wrong Mark on the Cam. The Plastic Cam Gears have a Large Dot Countersunk Into the Plastic. Did you De-Glaze the Cylinder when the Piston was Out? To Properly Set the Valve Clearance; 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). 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*** I have had Better Performance Out of the Mowers and Less Burnt Valves Using these Settings. Be Sure the Piston is at TDC on the Compression Stroke.** 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. On Some Engines you can Us a Straightened Coat Hanger and Feel the Piston. Be Careful and Dont Jam the Wire in the Cylinder. Usually the Piston will Push the Wire Out of the Spark Plug Hole with No Problems. 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. Have a Happy Holiday Season and May the All Mighty Bless You and Yours. Be Safe and Happy. 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. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: John,
Thank you for the quick response.
As to the timing mark on the cam, I'm right there with you. It should be between the teeth of the cam gear, but it's more on the tooth than anything. I lined it up with the one I thought it should be initially. I went ahead and pulled it back apart and put to the only other possibility and ended up with the same results. It backfired through the carb, and then just continued to turn over.
I'm at a loss at this point. It really acts like a timing issue, and I made no adjustments to the carb whatsoever. I've checked the lash on the valves many, many times with no avail.
BTW, I thought about a rehone, but it's a low hour engine, and had no real glazing to speak of,even with the lack of oil. It has good compression.
I've also included a link to the cam gear and the infamous mark. I've never seen one this iffy. Again, thanks for the help.
http://img372.imageshack.us/my.php?image=1001761ro1.jpg
Jason
AnswerHello Again Jason:
After Viewing the Cam Mark, I Suggest it be Placed so the Gap to the Left is Used. Are you Sure the Engine is at TDC on the Compression Stroke when you are Setting the Valve Clearance? Have you Tried; Pouring a Small Amount of Gas Into the Carburetor Throat while Holding the Throttle at Full. Still Holding the Throttle at Full, Try to Start the Engine. If the Engine Starts and Quits, then Remove, Disassemble and Soak the Carburetor Overnight in Carburetor Cleaner (I Use Gunk). 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. Have a Happy Holiday Season and May the All Mighty Bless You and Yours. Be Safe and Happy. 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. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
