Blowing oil out of breather

[Cfs]

It appears this would be a good engine to get familiar with your leak down tester. Not likely but A bad breather valve can cause such.
My OTC has saved me lots of time, especially not having to do a take apart inspection, such as worn rings, leaking valves, and quickly determining if a engine needs to be salvaged for possible parts vs repairing.
I think sometimes when first getting familiar with a leakdown tester people try to use too much air pressure during the FIRST TEST.

Since you already know this engine is a smoker, would be interesting to me too see if the leakdown shows leakage past the rings.
Sometimes too much oil on the rings or cylinder wall (from a severe oil burner) will not give a true really bad leakage but will indicate marginal. (because the oily bore raises the compression)
I give the cylinder a flush with carb cleaner or gas to flush the oil and re-test.


On OHV engines I disable the valve train so as the valves never open and do a leakdown of the complete piston travel, instezad of just doeing the leakdown at TDC. (as suggested by StarTech) This also help get the bore less oily for a leakdown.

So I pulled the head and found a lot of carbon around the exhaust valve. I cleaned up the valve heads and the beveled surfaces of the valve and the valve seats. I suppose I could have tried to remove the springs and lap the valves but I didn’t want to mess with pulling the breather as it always seems like I tear the breather gasket…anyway it seemed like the valves were seating well and there was no scoring of the cylinder walls. I put the head back on and hooked up to my Harbor Freight Leakdown Tester and it would not show any reading on the Leak gauge. I think I bought it 7-8 years ago and never used it. I did have 100 psi on the inlet side and as I moved the flywheel I could hear the air leak from the intake side and when rotated closed the leaking stopped. Same thing with the exhaust side when rotated to close the exhaust valve the leaking seemed to stop. I had to charge the battery overnight so the next day it started right up and I let it run for 20 minutes. I had a little smoke when I first started it and it stopped after a few minutes and ran pretty much smoke free after that? I did not have the oil saturated air filter on the engine would that make a difference? I placed my finger over the outlet of the breather hose where it connects to the base of the air box and I could feel a steady flow iof air but no smoke or oil spitting from the breather like I had a few days earlier. I was not able to put a full load on the engine (mower engaged) since the mower belt is broken. I will get a belt and an air filter installed and check it under load. I really want to learn how to run a Leakdown test and I have a new tester on order. The one I have is a US General stock number 94190. I think I paid less than $25 HF no longer carries the US General branded items and now sells a Maddox branded version for $84.95. I have noticed that HF has developed a dozen or more brands trying to do a Good Better Best and charging a whole lot more than their Pittsburgh brand and often the items are virtually identical! I suspect that Sears closing created a lot of opportunity to raise prices.

Anyway I am wondering if there could have been a lot of oil gas mix in the breather and muffler that would explain the smoking and oil spraying out of the breather hose
Spit

 

[Forest#2]

The things you were inspecting is one good reason to do a LEAK DOWN TEST FIRST.
You will reach for your new leak down tester quite often when you start playing with engines.

Like I mentioned most people at first inject to much air pressure when getting familiar with a leak down tester.
Do tests in increments of like 40, then 60, 80, etc. Also use your ears as well as watching the leak gauge.

Make sure your oil is not thinned out from gas contamination.
This will produce smoke for awhile until the rod turns loose.

 

[Cfs]

The things you were inspecting is one good reason to do a LEAK DOWN TEST FIRST.
You will reach for your new leak down tester quite often when you start playing with engines.

Like I mentioned most people at first inject to much air pressure when getting familiar with a leak down tester.
Do tests in increments of like 40, then 60, 80, etc. Also use your ears as well as watching the leak gauge.

Make sure your oil is not thinned out from gas contamination.
This will produce smoke for awhile until the rod turns loose.

Thanks for the reply. I am looking forward to mastering the Leakdown tester. One question I have… how do you recommend positioning the piston to TDC on a L head engine…and then anchoring it onto TDC.
I saw a video that advised using vise grips on the engine output pulley. There was definitely too much pressure with 100 psi on the piston to hold the flywheel by hand. I am a novice and would benefit from your experience on this.

This engine is a vertical 12.5 HP Briggs and it has the common double stacked pulley… top for transmission and lower for mower deck. I’m just asking what methods to prevent the engine from rotating you recommend

Spit