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Small Engines (Lawn Mowers, etc.)/OHSK55 engine races and will not run


QUESTION: This engine is on a yardman snow blower. Tecumseh oshk55-69504a.
New plug, and a new non oem carb. Starts right up but the engine "races" when on full throttle. I have the factory service manual, but cannot find any adjustment or picture of how the linkage is actually supposed to be. The linkage is what I suspect. Idle is ok, but only when the choke is on the first notch. Ideas??

ANSWER: Were there multiple holes in the carburetor butterfly shaft to connect the throttle linkage?  Most have several the throttle connect in the same hole as the old carb?  You should be able to see some wear on the old carb where the linkage went through the butterfly shaft hole.  A flashlight may help you see wear, out of round or shiny wear marks.

Did you mess with the governor arm at all?

Are familiar with the static governor adjustment?

Let me know.

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

QUESTION: I actually took a picture of the old carb before I disassembled it. So I have the rod back in the same place. I further inspected the gov arm and it is real loose and wobbly where it comes out of the block. The only screw to attach the arm to the shaft is tight... I do not know about the static adjustment, Easy to explain?


From page 23 (top) of the service manual:  With the engine stopped, loosen the screw holding the governor lever to the governor shaft clamp. Push the governor lever to move the carburetor throttle plate to the wide open position. Rotate the governor clamp counterclockwise on all overhead valve engines covered in this manual. Hold the lever and clamp in this position while tightening the screw (diag. 2)."

Service manual URL:

I'd start with the static adjust first.

Here is the Briggs link:

Same procedure on all small engines as described is paragraph 3.


Small Engines (Lawn Mowers, etc.)

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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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