QuestionQUESTION: Craftsman 917.270960, B&S 461707 Type 0145-E1 (20.5 HP)
Mower wouldn't turn over last fall. Finally got to working on it this spring. Changed Solenoid but wouldn't start. Removed starter and found starter worked. Reinstalled starter and found flywheel stuck. Loosened flywheel with wrench on flywheel nut but flywheel sticks for half a rotation and moves with difficulty for half a rotation, even with plugs removed. Starter will rotate flywheel for loose half of rotation but not for sticky half of rotation. Based on other questions and answers, sounds like it needs a valve adjustment. Seeking confirmation or other recommendation. Also, valve adjustment beyond my limited experience. If you know of any descriptive web sites that would be helpful. Thanks in advance.
ANSWER: Hello Keith:
From your Description it Does Not Sound like the Valves are Causing this Problem. Remove the Blower Housing and Check the Clearance between the Coil and the Flywheel. If the Engine is Not Turning Over Freely with the Plug/s Removed, then Either the Crankcase is Over Filled with Oil, the Coil is Striking the Flywheel or the Crankshaft is Bent (Badly). To Check the Crankshaft, Remove the Spark Plug. Tilt the Mower so the Plug Hole is Facing Up. Have Someone Turn the Engine and Watch the Blade Bolt. If the Bolt Stays True, then the Crankshaft is Good. If the Bolt Wobbles, then the Crankshaft is Bent. Depending on How Bad the Crankshaft is Bent will Determine if the Engine Binds as you Described. 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: Thanks for the quick answer to the first question. A very important fact I forgot to mention in the initial question is that we got the motor to start after we reinstalled the starter. It ran for about 30 seconds and then shut down quickly. It was running smoothly at the time.
Today, we checked the oil level and it is fine and the flywheel does not seem to be touching the coil. We checked the crankshaft and it appears to be straight. It seems that the crankshaft has loosened up somewhat since we last tried turning it.
Today, we tried starting the mower while jumping it with a car battery to get more power than the riding mower battery. Without the plugs, the flywheel rotates freely and at a good pace. With the plugs in, the flywheel gets stuck when the magnet on the flywheel lines up with the Armature-Magneto (nothing is touching).
We took the head cover off for cylinder #1 and this flywheel position seems to coincide with the valves being closed and the cylinder at TDC. I tried starting the mower with just the mower battery after reinstalling the cylinder head cover. The flywheel slowed down at the same place but didn’t stop. The mower didn’t start though.
I hope to change the fuel filter, add new fuel, and get some starting fluid to see if the mower will start now that the flywheel seems to have loosened up a little.
Thanks in advance for any more advice on what to investigate that could be binding the crankshaft at this one location.
ANSWER: Hello Again Keith:
If the Starter is Good (Load Tested) and the Crankshaft and Coil/Magneto are Not Striking the Flywheel, then Set the Valve Clearance. **Remove the Carburetor and the Crankcase Breather/Vent (# 8-1) and the Valve (Stem) Cover (# 8-2) so you have Access to the Valve Stems, Springs and Keepers. Set 1 Cylinder to TDC on the Compression Stroke. Using a Blade Style Feeler Gauge, Check the Clearances. The Intake should be .004in - .006in and Exhaust .007in - .009in. If the Feeler Gauge will Not Slide Between the Valve Tip and the Tappet, then you Must Reset the Clearances. **You Will Require a Small Engine Valve Spring Compressor to Remove the Springs and Keepers from the Valve Stems.** Some Engines Use a Valve Keeper that is like Automotive Keepers (2 Cone Shaped Keepers that Set in the Valve Retainer/Rotocoil Assembly)and the Other Style is a Slotted Retainer that is Moved (once the Valve Spring is Compressed) to the Larger Opening in the Retainer and the Retainer Slips Over the Valve Stem Tip for the Valve to be Removed. Remove the Heads. Set 1 Cylinder so the Piston is at TDC on the Compression Stroke And Check the Clearances Between the Valve Stem Tip and the Tappet. The Clearances are as Follows: Intake Valve Clearance is .004in - .006in and the Exhaust is .007in - .009in. You have to Lightly Grind the Valve Stem Tip and Place the Valve Back Into the Engine (you can Hold the Valve Seated by Hand) and Check the Clearance Until you Reach the Required Clearances. Once the Valve Clearances are Reached, Re-Install the Valves on that Cylinder and Turn the Other Cylinder to TDC on the Compression Stroke and Set that Cylinders Valve Clearances. Once that Cylinder is Set, then Re-Assemble the Engine.** This May be One of the First Model Engine that was a Non OHV Engine that Used the Compression Release. I am Researching this to be Sure and will Follow up to you if this is Not the Case. 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: Thanks for the info so far. I managed to get the mower started today after spraying some starting fluid in the spark plug holes, changing the fuel filter, and manually adjusting the flywheel so that it was at a location furthest from the sticking point. You may recall I reported that the flywheel gets sticky at one point in the rotation. I ran it for about 25 seconds before I shut the mower down. It ran very smoothly. I figured that tomorrow I would drain the fuel tank and use new fuel tomorrow to mow the lawn.
I decided to try to start it one more time and the flywheel was sticking in the same location. During the entire rotation with a wrench on the flywheel nut, the flywheel was sticking. After about two rotations it seem to be loosening up. I suspect that after a few more rotations, I will get it loose enough to start it, at least that is what has previously happened.
I suspect that I will get the mower started tomorrow by rotating the flywheel a few more times and adding some starting fluid to make sure it starts before the flywheel hits the sticky spot but obviously this isn’t a good permanent solution. Particularly since once I put all the sheet metal housing back on the motor, I won’t be able to get to the flywheel nut to rotate the flywheel before starting it each time.
Any idea why the flywheel would be getting sticky at a single point.
AnswerHi Keith:
There May have been Carbon on the Piston Top that came Loose and Lodged in the Cylinder at the Point where the engine Starts to Bind. The More you Turn the Engine the More Smooth the Carbon becomes and the Easier the Engine Will Turn until the Rings Cut the Carbon Down and the Engine will Start to Turn Smooth Again. It is Rare for this to Happen, but I have Seen it Occur Several Times Over the Years. 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
