Lube system purging

Hi Roger,

I’m doing the five year rubber replacement and planned to purge following the January 2021 Installation Manual, which states purge then do the valve check. If a soft valve is found, run the engine at 3,500 rpm and recheck.  But the July 2021 SI states purge, run the engine at 2500 rpm, then do the valve check.  I assume I should follow the SI as it has a later date than the IM ?
Jim

Anyone? Bueller?

The primary difference in the two methods is that following the SI assures that the lifters are checked after the engine is run.  Following the Rotax rules, yes, always use the latest document.  If you feel better about it you could combine the two and check the lifters before and after an engine run.  Remember to make sure the side by side valve covers are not touching each other when you put them back on. You should be able to slip a business card between them.  

Well, it’s done. After 60 hand prop rotations without pressurizing the tank and achieving no cockpit oil pressure indication whatsoever, I decided to pressurize. So then I learned, unless one pushes down on the oil tank cap whilst pumping air into the oil tank via the tank vent tube, one will not achieve any meaningful minimum tank pressure (5.8 psi). 20 psi into the tank, less than 4 psi effect in the tank due to the inherently leaky cap. So there I stood, pushing down on the tank cap to maintain about 8 psi while turning the prop. That did the trick after 20 rotations.  Sniff. Wah. Anyone got a Kleenex?

Hi Jim,

Just wondering of your cap seal is overly worn, thereby leaking more air than normal?