QuestionQUESTION: I removed and cleaned carburetor on a Tecumseh HM80, 155334-M 8 hp. engine. (ON a yardman model 31383-8 snow blower) It was surging badly. Works excellent now but I'm not sure about how the governor control arm was supposed to be bolted on (at the engine block). I just lucked out? 2 control rods connect to the extension arm, no problem there, one to carburetor and one to throttle control lever There is one screw and nut that goes thru the "stub" governor arm at the engine, but the extension arm can be tightened at a wide variety of pivot positions on that. What was supposed to be the position of the governor extension arm before I tightened the screw/nut to the shorter governor arm ? A link to the manual, pdf, page 36 box 22, depicts the carburetor and the linkage to the governor to the left upper corner. However, the extension arm arm is not fully depicted as it has the attachment point to the stub governor arm with the single screw/nut just off the page. http://www.cpdonline.com/692509.pdf
ANSWER: Hello Eric:
>>The Following is an Instruction File I Made for Setting the Governor Arm Correctly. Any Input is Appreciated.
>>If you Removed/Loosened the Governor Arm from the Governor Shaft or Put the Linkage in a Bind when the Carburetor was Removed, 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.**
>>You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.outdoordistributors.com/ and Select the T. Then Select Tecumseh. Then Select Don't have Part Numbers. Then Enter the Model Numbers HM80-155334M. Then Select your Model and Download the File for Online Viewing.
>>If you Hit a Snag or this Does Not Correct the Problem, I Hope to be Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 3 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. All Follow up Questions are Accepted at Any Time. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: John...Thanks so much for the pdf parts list and description of governor adjustment. The part list is a little fuzzy at the governor arm breakdown, and I need to clarify your response. The governor shaft is vertical and extends up about 1/4 inch above a pinch bolt and there is a flat arm about 1 inch long also held in place. I have not touched that pinch bolt to the shaft or short arm. Another flat arm, about 2 inches long, attaches to the first arm. There is a single screw and nut connecting the two. If I understand you correctly, rotate the short governor arm (the one inch one) full clockwise, and tighten the 2 inch flat connecting arm to it AFTER pulling that arm out to make the carburetor open full throttle ? The position of the actual throttle control lever doesn't matter at this point? There is a second control arm that parallels the carburetor control arm and it goes from the 2 inch lever to the throttle control lever area. Essentially, sounds like the 2 inch lever is tightened to the inch governor lever in "full" speed mode to include the governor and the carburetor throttle. After tightening and releasing the arm, the throttle will spring to the idle position with the governor slowing back with it (counterclockwise). You've been very helpful to date explaining a detailed "domino" adjustment ! Thank you so much !
AnswerHello Again Eric:
>>You are More than Welcome for Any Assistance I can Give you.
>>You are Correct.
>>Since you have Not Moved the Short Link on the Governor Shaft, you Attach the Other Flat Governor Arm while Holding the Governor Shaft Clockwise and the Throttle of the Carburetor Full Open.
>>The Governor will cause the Throttle Plate of the Carburetor to be in the Full Open Position whenever the Engine is Not Running.
>>Once the Engine is Started, the Governor Pulls the Throttle Plate to the Proper RPM Set by the Throttle Cable and Linkage (example: if you have the Throttle Cable Set for Idle, the Carburetor Throttle Plate will be Full Open and Once the Engine Starts, the Governor will Pull the Throttle Plate to Idle).
>>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.
>>Your Engine uses the Mechanical Type Governor.
>>As Always, If you Hit a Snag or this Does Not Correct the Problem, I Hope to be Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 3 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. All Follow up Questions are Accepted at Any Time. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
