Small Engines (Lawn Mowers, etc.): engine runs with full choke only, blown head gasket, steering wheel puller

Question
QUESTION: My 20 h.p. kohler engine is only 3 yrs old and worked great until it quit without warning.  Now it will start and run, but very poorly, with full choke and 3/4  to full throttle.  If you try to back off the choke, the engine quits immediately.  Enough unused fuel builds up in exhaust pipe to ignite.
I have done the following, with no improvement.
1. replaced fuel
2. replaced fuel filter
3. replaced fuel pump
4. soaked carburator and installed carb kit.
5. replaced spark plugs.
Any suggestions?

ANSWER: Hello Pete:

Send me the Model and Type Numbers Off the Engine, Please. With these I can Locate the Proper Manual and Better Assist you. 1- However, It can be the 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).** 2- A Blown Head Gasket. 3- The Carburetor Jet Might Still be Restricted. 4- A Valve Problem. 5- A Compression Problem. With the Model and Type Numbers I can Assist you Better. I'm Leaning Towards a Blown Head Gasket, Carburetor and Lastly the Flywheel Key, as these are the Most Common Causes for the Problem you Described. Thanks.

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 9pm EST (US). My New Day Starts then. Thanks.

Respectfully

John

---------- FOLLOW-UP ----------

QUESTION: John,
Thanks for the quick response and great advice.
Model # CV20S
Type e11^97/68SA^2002/88^0279^00
Maybe this last clue will help sort things out: During the midst of all of this,(after changing fuel filter & spark plugs, but before doing anything else) after warming up, the mower ran just fine and normally for about 10 minutes before encountering some high grass.  Instead of laboring under the load, the engine just quit--and went back to the same problems as described.
Thanks again.  
Pete


Answer
Hi Again Pete:

You can View a Breakdown/IPL of this Engine at this Site Addy; http://www.kohlerplus.com/login.asp and Select Enter as Guest. Select Command Twin Engines. Then Select CV20. Then Select your Engine from the List Provided. Check the Fuel Shut Off Solenoid in the Bottom of the Carburetor. 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. If the Solenoid Heats Up, it will Cause the Problem you Described. If the Solenoid is Not the Cause of the Problem, then Check the Compression. Check for a Blown Head Gasket. If this Engine has 2 Coils/Magnetos, then Check for Proper Fire on Both Coils/Magnetos. It Sounds like a Carburetor or Head Gasket Problem. If these are Good, then Complete the Checks I Listed in my Earlier E-mails. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John