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Small Engines (Lawn Mowers, etc.)/slight camshaft [bump]onintake valve function


have 7.4 year old Tecumseh 5.5 hp on a yardman snowthrower.
after nearly 8 years of use the power and compression went way down.
 pulled the flathead head.ground and seated exhaust valve  at10 thousaands clearance. no problem there.
exhaust valve had to grind shorter for clearance.
 then ground intake valve for .010 far so good.
noticed about half way up the intake valve lifted very slightly for I would say about 5 degrees crank turn in the middle of the upward compression stroke..I ended up having to grind valve clearance to .030 to get rid of this glitch

That pump you saw was most likely the compression release.  All small engines have a compression release and almost all lawn/power equipment use a mechanical compression release as part of the cam lobe grind.  There have only been a few engines that used a secondary device, usually mounted on the cam, as a compression release.

What is engine model and spec number?  Will the engine still start?


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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