QuestionI have a 6 year old Saber [John Deere] with a 17.5 Kohler with about 250 hours on it.
Off the block:
Serial No. 3215130383
Spec. No. PS-27509
Model No. CV 491S
Family 2KHXS .4902GB
Off the Chassis:
Model 17.542HS
It was running good when I put it up last fall. Went to start it last week and it won’t start. Cranks without firing in run and backfires thru the carburetor with the choke applied.
Assuming the carb is good, what would cause the backfiring? Why isn’t it backfiring without the choke?
Gas is fresh, spark is good and electrical is good. The solenoid in clicking and the spark plug is new. Cleaned the carb inside and out. Linkage is working correctly.
I’m wondering if I don’t have a few problems with it.
1) Looks like the choke valve [guess that is what you call the round disk on the shaft] is has three holes on it. Is it missing a flap, or cover of some sort, that normally covers these holes? Maybe it was blown off by backfiring? Could this cause the fault I have?
2) With the solenoid, bowl, and float removed I’m looking at the port the solenoid threads into, there’s a small tube inside the port looking up at me but it is off center. Normal? Does the solenoid plunger close this port on shut own?
3) Read another post that suggests that the solenoid could be left off so long as the flow thru the side hole isn’t blocked. Is that correct?
Any help or suggestions you can offer?
AnswerHello Al:
This can be Caused by a Dirty Carburetor, a Sticking Valve or a Damaged Flywheel Key. I Suggest you; 1- **Remove, Disassemble and Soak the Carburetor Overnight in Carburetor Cleaner (I Use Gunk). 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) and Needle Valve and Any Adjustment Screws that Go Into the Carburetor Body. The Welch Plugs Do Not have to be Removed. 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. Install New Parts if Required.** 2- Check for a Damaged Flywheel Key. ***Remove the Blower Housing (metal engine cover). Remove the Flywheel Nut or Starter Cup (Depends on the Model). Now Attach a Steering Wheel Puller to the Flywheel Using the Threaded Holes in the Flywheel. Tighten the Puller. Now Hit the Puller with a Hammer. Repeat this Procedure Until the Flywheel Pops Up or can be Lifted Off the Crankshaft. On Some Models you Can Not Use a Puller and Must Use a Pry Bar and a Pipe Cap that is Slightly Larger than the Crankshaft. Place the Pipe Cap Over the Crankshaft to Protect it. Place the Pry Bar Under the Thick Section of the Flywheel and Pull Up Against the Flywheel. **BE CAREFUL DO NOT PUT A HOLE IN THE BLOCK UNDER THE FLYWHEEL** Now Hit the Pipe Cap that is on the Crankshaft (covered with the Pipe Cap). Repeat the Procedure Until the Flywheel can be Lifted Off the Crankshaft. *** 3- Remove the Cylinder Head and Make Sure Both Valves are Moving Properly. If Not then Lubricate the Sticking Valve with Transmission Fluid Until it moves Freely. These are the 3 Most Common Causes of your Problem in the Order in Which they Occur the Most Often. The Choke Flap is Fine. It is Supposed to have the Holes you Described. From your Description, it Can Not be the Solenoid, so that is a Non Issue here. You can Check the Solenoid as Follows: If the Carburetor Shut Off Solenoid has Current, then Remove the Carburetor Solenoid and Go to the Hardware Store. Purchase a Bolt of the Same Diameter and Threads. It Needs to be 3/4" Long. 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 Jets. You can View a Breakdown/IPL of the Engine and Mower at this Site Addy, http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.H... and Enter the Model Numbers (Sabre) and Click Find. Then Select your Model from the Search Results Area. Then Select the Sectional File. Then Select the Section of the Mower you Wish to View Online. 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
