QuestionQUESTION: Hi John,I bought a Kohler engine and was told it was a 12hp, but I am not sure? It had been repainted so all of the stickers are gone. It does have K301 cast in the block above the shaft. The reason I ask is, I bought my Wheel Horse new in 1979 and it has a 10hp Kohler engine. It has a sticker on the flywheel cover that has Model K241AS but it also has K301 cast in the block. Is there any other way to tell if the one I bought is really a 12hp and not a 10hp, or even a 8hp?
Second question, This is a new short block and the guy put all the stuff from his old engine on this engine but couldn’t get it running. I found he had some wires mixed up on the tractor and it started right up. The problem is the RPM’s will go to high. I don’t think he has the governor linkage set up right. Can you walk me through the correct way to set it up?
Last question, I have a IDC model 375 trimmer that idles great but as soon as I give it gas it dies. It will start right back up but die as soon as I give it gas. I took the air cleaner off, same thing. I took the muffler off, same thing. The plug looks almost new. Any thoughts on this as well?
Thanks, Robert.
ANSWER: Hello Robert:
1- The Casting #K301 Covers a Range of Kohler HPs. Usually the K301 Cast Block Starts at 10 Hp and Goes to 18 HP. Without any Model and Specification Numbers, the Only Way to Truly Tell the Correct Engine HP is to Get the Bore and Stroke of the Engine. Did you Check the Blower Housing (Metal Engine Cover) for Model Numbers Stamped Into the Housing? 2- The Following is an Instruction File I Made for Making this Adjustment. Any Input is Appreciated. If you Removed/Loosened the Governor Arm to Remove the Carburetor, then Reset the Governor. **To Reset the Governor; Loosen the Governor Arm Bolt and Turn the Governor Shaft Clockwise Until it Stops. Using the Governor Arm Hold the Carburetor to Full Throttle. Now with the Shaft Full Clockwise and the Governor Arm and Carburetor Held at Full Throttle, Tighten the Governor Arm Bolt. If the Engine Still Runs Full Throttle, then Reverse the Rotation of the Governor Shaft, but Still Hold the Carburetor at Full Throttle with the Governor Arm. If it Still Runs at Full Throttle, then Check the Internal Governor.** 3- A Bad Fuel Filter or a Dirty Carburetor are the Main Causes for this Problem if the Exhaust Port, Muffler and Spark Arrestor Screen are Clear. The Cost of the Cleaning Solution I Use is $30.00us @ Gallon (I Use Gunk). The Gallon Can Comes with a Tray for Small Parts and the Carburetor Fit Nicely. Most Times a Carburetor can be Soaked and Cleaned and with the Float, Needle Valve and Other Carburetor Components being Soaked in the Cleaner with the Carburetor Body; there are No Parts to Replace on this Carburetor. If you Soak and Clean this Carburetor and the Float Needle Valve Still Does Not Stop the Gas Flow Properly, then Purchase a Needle and Seat Kit and Replace it. The Following is a Basic File I Made for Cleaning Carburetors. Any Input is Appreciated. The Most Common Cause is; The Carburetors Internal Passages are Restricted by Varnish that Gas Forms Over Time. This Varnish is in Layers. To Properly Remove this Varnish you have to Soak the Carburetor. The Following is a General Instruction File for Carburetor Cleaning. Even though the Carburetor Looks Clean, the Internal Passages May be Restricted with Varnish that Gas Causes to Build Up over Time. I Suggest you Make Sure the Gas is Free Flowing to the Carburetor Inlet Port (if the Model does Not have a Fuel Pump). If the Gas is Free Flowing to the Inlet Port, then **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), Needle Valve and Needle Valve Seat if Applicable. This is a Flat O-Ring Located in the Inlet Port the Float Needle Rests in. Use a Strong Wire with a Slight Bend to Remove the Old Seat. Sometimes a Small Pocket Screw Driver can be Use Also. The New Seat will have a Slightly Beveled Side and a Flat Side. The Flat Side goes Towards the Carburetor Body when Inserted into the Inlet Port. Spray the Seat with Spray Lubricant to make Installation Easier. The End of a Drill Bit that is Slightly Small than the Seat can be Use as an Insertion Tool. Wear Gloves or Use a Rag when Handling the Sharpened End of the Drill Bit. Remove 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.*** (Do Not Use High Pressure Air for the Zama Carburetors, they have Check Valves for the Primer and these are Usually Blown Out of the Carburetor if Not Careful. Allow the Zama Carburetor to Set on a Drip Pan and Dry)***. ****All the Carburetor Adjustments are the Same for Lawn Mower and Trimmers. There are Several Location for the Air Mixture Screws. The Idle Air Mixture Screws are Usually Located at the Top of the Carburetor Bowl and the Top of the Carburetor Body. If the Main Air and Idle Air Mixture Screws are Side by Side on the Side of the Carburetor, then the Idle Air is the Farthest from the Engine. The Main Jet Air Mixture Screw is Located in the Bottom of the Carburetor Bowl or Beside the Idle Air Screw on the Side of the Carburetor Body. Some of the Older Model Carburetors have the Main Jet Mixture Screw Straight in from the Top of the Carburetor Body (this is Rare anymore). If you have Cleaned the Carburetor (Disassembled and Soaked Overnight in Carburetor Cleaner (I Use Gunk). Then Blow Out the Passages with Compressed Air and Install a New Kit if Required. Now Setting the Air Mixture Screws: ****Turn the Idle Air and Main Air Mixture Screws In Until SNUG **Do Not Jam** Then Reverse Both Screws 1 1/2 Turns. Holding the Throttle Full Open, Start the Engine. Turn the Main Air Mixture Screw Clockwise Until Proper Revs are Obtained. Occasionally you May have to Turn this Counter Clockwise to Achieve the Proper Revs. Now Allow the Engine to Idle. Set the Engine Idle Screw (Not Idle Air) so the Engine will Stay Running if Required. Now Set the Idle Air Mixture Screw so there is No Hesitation when Throttling from Idle to Full Throttle. Reset the Engine Idle if Required.**** If This Carburetor has a Single Air Adjustment. Use the Section Above that Pertains to Full Throttle RPM Air Mixture Screw and then Adjust the Screw if Required to Eliminate Any Hesitation when Throttling from Idle to Full Throttle. This file was Intended to Give you the Basic Carburetor Cleaning Instructions and May Not Reflect Your Carburetor Components. If you have Questions, Please Ask. 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: Hey John, just to follow up. 1-The Blower Housing (shroud that covers the flywheel?) is from his old engine. Thanks to you, I know it is at least a 10hp and that’s OK.
2-It looks like the governor was set right. After looking at the Kohler owner manual, that came with my Wheel Horse, it appears that it might be the “high speed stop” on the speed control bracket that may not be set right. What do you think, before I make any adjustments?
According to the manual the “Maximum allowable speed for most engines is 3600 RPM.
3- The garage I use for car inspection has a parts cleaning tank, I’ll see if they will soak it over night for a nominal fee. And May the All Mighty Bless You and Yours As Well.
Thank you, Robert
AnswerHello Again Robert:
I am Glad I was Able to Assist. Even with the High Speed Stop Set Incorrectly, the Internal Governor will Regulate the Engines Speed to No More than 3800 - 4000 RPMs. If the Engine is Screaming at Full Throttle, then Usually the Cause is a Bad Internal Governor or the Governor Requires Resetting (you have already preformed this). You can Use the High Speed Stop on the Control Bracket to Set Full Throttle Max RPMs, But if the Internal Governor is Bad, you will Find Out within a Few Uses. ***The Governor System Behaves like an Unending Tug of War between One of Two Governor Springs, which Pull the Throttle Toward the Open Position, and a Spinning Crankshaft, which Tries to Close the Throttle. When the Load on the Engine Increases - a Typical Example is when you Move your Running Lawn Mower from the Driveway to the Grass - Crankshaft Revolutions Drop. But the Governor Spring is Still Tugging, Causing the Throttle Plate to Open. In Response, a Larger Volume of Air-Fuel Mixture Enters the Carburetor, Increasing Engine Speed to Compensate for the Increased Load. The Crankshaft Speeds Up, and the Tug of War Resumes, until a New Equilibrium is Achieved. With Each Change in Load, the Tension Between the Governor Spring and the Load Brings about a New Equilibrium, known as the Engine's Governed Speed. Neither Side Wins until the Engine is Shut Off. At that Point, without the Crankshaft Spinning, the Governor Spring Pulls the Throttle to the Wide-Open Position. Two Types of Governors are Common on Small Engines - Mechanical and Pneumatic.*** 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
