by Arkie » Mon Oct 10, 2022 9:26 am
Before you pull the head take a close look at the exhaust rocker/pushrod action and even set the exhaust lash at max specs and test again.
If you see no leakage from either valve or the leakage switches valves as the crank is slightly rotated and the ACR is not involved would make me want to think about camshaft. (instead of pulling the head) You say moving the crankshaft slightly will get a seal on the intake and exhaust but not both at the same time.
Camshaft lift lobes not acting correctly?????????????
At least the Leak down is showing some results of what the engine is doing when running.
I'm not that familiar with those 21, 31, 33 series of Briggs cams other than the fact some can do some strange things and I have a 31 that ruined the engine when it failed and a low hours 33 series engine that the ACR is not working at all and a 31 donor engine for the 33 maybe.
I see several china clone cams for sale and have heard of some sad stories about those. Seems some of those Single cylinder Intek cams last forever and some shell out at low hours. Mine failed at low hours. (the ACR)
I'm not saying your cam is bad, but suspect of something amiss, I'm just saying that you need to inquire more before pulling the head.
Just a heads up if you ever go looking for a replacement Briggs 33 series camshaft. The oil pump type engine and the non oil pump engine list the same part number. You have to make sure get the correct replacement if it has the oil pump.