make sure you run that test with the breather hose disconnected from carburetor so you don't get fooled by air coming from crankcase via breather. - If it is coming from breather tube, then it's obviously coming from crankcase, not carb..38racing wrote:I know I did things a bit out of order here. Friend feels that his briggs 28 series OHV is consuming oil. It's 94 and well used but my daughter's had same symptom a couple summers ago and after checking a couple things I pulled the head. I found early stage head gasket failure. I replaced it and the oil consumption ended. Given age of friend's I figure I might as well start with the head gasket. It appeared to be fine. I then measured bore and it wasn't even close to the reject . No scratches on the cylinder. Not a lot of carbon buildup either. So I removed the valves and cleaned the head. Valves and seats looked ok. I lapped valves and reassembled. Decide to do leakdown at this point but had an issue with my tester. I updated the thread in the tool section about that. Friend dropped by before the leakdown and I discussed what I found. Adding oil isn't a big deal for him but he was concerned of an engine problem . Turns out he is using synthetic oil but in 5w30. That maybe could account for some consumption in an older engine. So the plan is to use only straight 30 from now on. So after discussion I get back to leakdown. I have piston at 1/4 past TDC compression. Both valves at spec. Intake at .004. I haven't set up yet for a good hold of the flywheel but at 30 psi I get 42 % leakage and it's clearly coming out carb intake. I guess that I am re-pulling the head to check the intake valve.
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