Engine Running Problem


Old 11-10-02, 03:36 PM
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Oil leak-what is this part : 3.5 HP Craftsman gas engine

3.5 HP Sears Craftsman gas engine for leaf machine-- There is a 3 inch by 1 and half inch cover metal plate located just above the muffler and screwed into the engine . The plate is held on by 2 phillips head screws . The plate covers the stems of the valves ; you can clearly see the valve stems and springs when the plate is removed.

Within 2 minutes of running the engine , oil spurts out of a vent hole in this cover plate . It appears that this cover plate may be acting as a pressure relief valve . There is what appears to be a 'reed type one way check valve ' in this cover plate. My trouble is that the reed type valve seems to be fatigued or stuck in the open door position. Any pressure that starts to build within the engine seems to force the oil to spurt out through the vent.

The oil was just changed . The oil is coming out yellow . The dipstick indicates just at FULL. Can anyone identify this part ? Function ? Replacement ?

model number of engine is 143 234262.

Last edited by stilllearning6; 11-10-02 at 04:03 PM.
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Old 11-10-02, 07:55 PM
J A Boggan
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I can tell you that the part you described is the crankcase breather. I'm sorry, but I don't know what your problem might be but you might try replacing it. A handy web site is www3.sears.com, where you can see an exploded view and a parts list. Whenever you put in your model number be sure and include a "dot" after the 143. Also, your engine is a Tecumseh equilvilant model number LAV35-40772K. Hope this may help in some small way. Unfortunately, the quality of the drawing is rather poor (at least on my computer), which is unusual. Also, the toll free number for sears parts is 1-800-366-7278.
Old 11-10-02, 11:29 PM
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Hello Stillearning6!

The part you described is the PCV valve. It regulates crankcase pressure. If it is stuck open, I suggest replacing it. This should cure the problem. Let us know how it goes!
Old 11-11-02, 01:15 AM
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Oil is coiming out yellow?
Old 11-11-02, 04:25 AM
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Thanks to all. " Breather Assembly " $21 part has been ordered thru Sears . Yes, oil is yellow because it was just changed. I can not understand what would cause this part to go / stay in OPEN position. It appears to be merely a tab of metal acting as a one-way swinging gate . I thought that a particle was wedged in the hinge section of it . Soaking in gas did not cure it.

I appreciate your input.

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