Oil on spark plug

Old 08-05-01, 08:22 AM
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I have a murray riding mower with a Brigss and Stratton mower. It is about five years old I think. I bought it about a year ago.

At first it would lose oil every time I used the mower. I would just add a little before the next time I used it to fill it up to where it should be according to the dip stick.

However one time I filled it a little to high and ran the mower. I don't know if it is coincidence but since this time I have had trouble keeping it running.

Everytime it stalls I pull out the spark plug and it is covered in fresh oil. I check the oil level and it is actually low. I fill it up to normal again and clean the spark plug but it is covered in oil again after 10 minutes. After this point it is immediately covered in oil every time I start it and move it a couple of feet.

I took of the cover to what I think would be the top of the two pistons and there is oil in there as well.

I don't know what to do next.

Please help.
Old 08-05-01, 07:59 PM
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Hello and Welcome Steve to the Do It Yourself Web Site and my Small Engine forum. I welcome your questions and hope to offer positive and helpful suggestions.

I doubt your once overfilling the engine crankcase caused the current high oil consumption problem. So rest easy on that note.

What you want to start off doing is checking the simple things first. Check the crankcase breather for any restrictions. The part will be located on the engines block. It should be rectangular in shape and held in place by two screws.

When you find it remove it. Clean it with engine cleaner if it's oily or clogged etc. There should be a hard fiber plate inside the breather. It should produce a slight click when gentle finger pressure is applied to it. Basically it's a one way check valve.

Inspect the cavity the breather is installed in also. Should be a hole going into the crankcase. Cleanout any restrictions, clogs etc.

Just below or at the carb will be the crankcase breather hose. Be sure the hose is cleared and connected. Checkout the ports both ends of the hose connections ports also.
Check the air filter also.

Consider the fact that the engine may have wornout piston rings and or valves. Hard prior useage and poor regular maintenance may have contributed to excessive engine wear.

You will need to do a compression check to determine the condition of the piston rings and valves. The correct procedure is to prewarm the engine, have the plug wires grounded, throttle wide open and allow only one compression hit.

The compression read on ONE compression hit is the value to use to determine a pistons compression. {{{I bet I'll get tons of emails with alternate opinions with that statement...haha.}}} Record the compression readings.

After you check all the above, reply back with the findings. Use the REPLY button to reply back. doing so will then allow this topic to continue one posting after another. It aides in following along with the topic.

Regards and Good Luck,
Accurate Power Equipment Company.
Small Engine Service and Repair Technician.
Personal Quote:
"If it ain't broke, don't fix it until it is broken!"
Bare in mind my company no longer services nor repairs lawn and garden powered equipment. Rest assured and fully confident, the help I offer you is based upon my prior years in this industry, with this type of equipment and is specific and accurate to the best of my knowledge...
Old 08-06-01, 09:19 AM
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Poor man's way to determine compression

I have read that on most B&S engines you can use the flywheel to determine if there is sufficient engine compression.

You'd rotate the flywheel a bit backward (say counterclockwise) and if compression was sufficient it would spring back forward.

I was like huh? at first when I read it, but I then read that this is the approved method from B&S !! I read it in a book I got at the library that was written by B&S people as well.


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