QuestionQUESTION: I have a 42 in Craftsman Mower. Model # -917271011. I recently changed gas tanks out on my truck and put the old gas in my lawn mower (It had rust in it). Just recently it started backfiring after it had warmed up (About 20 min into mowing) and then quits. Is this a simple fix or am I better off rebuilding the engine (If this gas is a coincidence and not the cause). Again, it runs fine until it warms up. The neighbor said this happened to him and it was a valve or something he JB welded back together and it ran fine. Thanks, John.
ANSWER: Hello John:
If this is Occurring at a Fairly Regular Intervals, then Check the Gas Tank Cap and Ensure it is Venting the Tank Properly. Check for Rust in the Gas Tank. The Rust Particles are Directed towards the Outlet Port of the Gas Tank. As These Partials Build at the Outlet Port they Restrict the Gas Flow to the Engine. As with the Gas Cap Venting the Tank; it Takes about 15 to 20 Minutes Before the Engine will Start Giving the Type of Symptoms you Described. If the Tank and Cap are Good, then Check the Engine for Fire at the Plug when the Engine Shuts Off Next Time. If there is No Fire, then The Coil/Igniter/Ignition Module is Bad. All 3 of these Items are Time Sensitive. It Takes Between 15 to 20 Minutes for Each of these to Cause the Problem you are Having with this Engine. Go to this Site Addy, http://www3.sears.com/ and Enter the Model Numbers in the Upper Left Search Box and Click Go. Then Visually Verify the Equipment and Click Continue. From this Page you can View Diagrams or Parts Lists for you Equipment. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.
Good Luck
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: I used the mower again tonight. Like clockwork, about 15 minutes into mowing the mower started to die. I quickly disengaged the blade and turned the mower to idle, the mower continued to run. Anytime I gave it more throttle, the mower tried to stall. Eventually, the mower did die. I quickly inserted the spark checker into the plug-wire and grounded the device, the mower had a good spark when engine was turned over with the key. Every time I tried to start the mower, it backfired and sputtered. Gas tank was cleaned and new fuel filter installed prior to this run. After I initially started the mower I made sure that the fuel filter was full of fuel (Stayed that way the whole time). I also noticed that after starting the mower for the first time, anytime I tried to give the engine more throttle, it did not rev the engine. It almost appeared like the fastest the engine would go is in the cutting speed position (About the half way mark). I do have access to a air compressor if I have to blow out carb. Thanks for your continued efforts.
ANSWER: Hello Again John:
Was the Gas Cap Venting the Tank? Do Not be Fooled by the Gas in the Filter. It can Still be in the Filter, but Not Getting to the Carburetor. Does this Carburetor have the Fuel Shut Off Solenoid in the Carburetor Bowl? If Yes, then Remove the Solenoid and Go to the Hardware Store and Purchase a Bolt of the Same Diameter and Threads; about 1/2 to 3/4" Long. Install the Bolt Instead of the Solenoid. Operat the Engine and See if this Corrects the Problem. If Yes, then Replace the Solenoid. **I DO NOT SUGGEST YOU OPERATE THE ENGINE LONGER THAN IT TAKES TO SEE IF THE SOLENOID IS BAD.** Sometimes the Solenoid will Overheat and Slowly Shut Off the Gas Flow to the Carburetor Jets. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.
Good Luck
Respectfully
John
PS I Forgot to Give you the Site Addy for the Engine Breakdown/IPL. You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.smallenginepartswarehouse.com/parts.asp and Select the Shop Online Parts Look Up. Then Select the Model Tab. Then Select the OEM and Enter the Model Numbers (CV15S-41567). Then Double Click on the Model in the Results Area. Now you can Select the Section of the Engine you Wish to View. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: Sorry this is taking so long. Gas cap has 2 tubes in it, I cannot blow or suck through either one. However, with the gas cap off, the problem still persists. Made the trip to the hardware store for the bolt. Started fine, however, shortly after the engine started the backfiring and stalled. When looking down the carb throat, I see gas spraying erratically when the engine starts to backfire and pop. If the carb jets are clogged with rust also, would it normally take 10 to 15 min to start acting up. Almost hopeless in the USA. Thanks, John
AnswerHello Again John:
No Worries. It can Sometime Take Several Communications to Locate the Cause of the Problem. The Only thing Left is the Valves. This Engine has Hydraulic Lifters; so the Valve Clearance is Not the Issue. The Issue is Weither a Valve is Burnt. You can Try Removing, Disassembling and Soaking 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, Float Pin, Float 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 Accidential Spillage. Then Blow Out the Passages with Compressed Air. Install New Parts if Required. If the Carburetor Cleaning Does Not Correct the Problem, then Remove the Cylinder Head and Remove the Valves from the Cylinder Head. Reseat the Valves and Replace if Required. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.
Good Luck
Respectfully
John
PS Do Not Go Hopeless Yet. LOL Thanks.
John
