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21 HP Briggs Smoking and leaking oil

#1

M

maphil

Craftsman ZTS 6000 with model 331677 Platinum engine started smoking intermittently and is leaking oil. It looks like the leak is coming from the fuel pump.?? The air filter was dirty and was replaced with a new one with no change. Compression wet/dry both 120 psi. Oil was filled to correct level and it used 1/4" on dipstick in about 20 minutes. It starts and runs good but engine will stutter every few seconds and a puff of smoke comes out of the exhaust. The mower is 6 years old and has only been used on a small yard. Photos attached.

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#2

M

mechanic mark

https://www.briggsandstratton.com/na/en_us/support/faqs/browse/engine-emits-white-blue-smoke.html

http://faculty.missouri.edu/~schumacherl/276781SingleCylinderOHV.pdf engine repair manual


#3

T

Tinkerer200

Probably head gasket. Yes it can have high compression and still have leaking head gasket. IF you have the equipment, a blow down test will tell for sure. Just need to lock the flywheel at TDC on compression stroke and blow in plug hole with rubber tipped blow nozzle at 20-30 lbs.Remove valve cover watch down push rod gallery, listen at oil fill tube, carb and exhaust. IF head gasket is leaking, it will be between the cylinder and push rod gallery.

Walt Conner

PS: Leaking oil, you need to wipe it clean and see where. Likely around oil fill tube or valve cover.


#4

M

maphil

Tinkerer200 said:
Probably head gasket. Yes it can have high compression and still have leaking head gasket. IF you have the equipment, a blow down test will tell for sure. Just need to lock the flywheel at TDC on compression stroke and blow in plug hole with rubber tipped blow nozzle at 20-30 lbs.Remove valve cover watch down push rod gallery, listen at oil fill tube, carb and exhaust. IF head gasket is leaking, it will be between the cylinder and push rod gallery.

Walt Conner

PS: Leaking oil, you need to wipe it clean and see where. Likely around oil fill tube or valve cover.
Click to expand...

The thing that bothers me is the oil leak. I have let it run for 15 minutes at full throttle with no visible leaks. After 15 minutes or so driving around the yard the fuel pump and deck below is wet with oil. I don't know if it is blowing up there or what. It is mounted up high with nothing else near it.


#5

T

Tinkerer200

I should have read closer, sounds to me like the fuel pump has a ruptured diaphragm.

Walt Conner


#6

M

maphil

Would it run if the diaphragm is busted?


#7

M

maphil

Head gasket was the problem.


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