Re: 318 Oil fill / dipstick tube leak
If oil is pushing out of the dip stick tube, sounds like there is excess pressure in the crankcase. Possible sources are, clogged breather tube. Check this first as it is the easiest to fix by cleaning and reinstall. Bad rings allowing combustion pressure past the piston into the crank case. Perhaps a compression test will confirm or eliminate this possibility. Over filled oil. This may be something to consider. This can also come from fuel leaking from the carb, into the crankcase. You can check by smelling the oil. If it smells like gas, look to the carb leaking gas.
Hope some of this helps ID the cause, and whatever the cause is, that it is easily fixed.
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