Small Engines (Lawn Mowers, etc.)/Oil seal leak


Kawasaki mod.757 25 hp. gas ............
Replaced crankcase oil seal but still leaks.
Is this because the crankcase doesn't have a return or drain - oil port behind the seal?
So the oil under pressure has no place to go.
Other 757 have this problem, ..... are you aware of this?

The seals are in good shape and so is the shaft.
The oil has to be under pressure for it to be able to come out that fast.

If oil is coming out that fact I would perform a crankcase vacuum check.  The crankcase should have a breather that allows internal pressure to vent out of the crankcase. This is a one-way pressure vent and the breather prevent atmospheric pressure from entering thus allowing the engine to generate a vacuum to keep the oil inside the crankcase.

I have not heard of this problem.  Are there any message boards discussing the issue?

Do you have a vacuum/pressure gauge or a manometer to check for crankcase vacuum or pressure?


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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