- Joined
- Oct 31, 1996
- Posts
- 904
- Type aircraft owned
- Carbon Cub FX-3
- Base airport
- KFCI
- Ratings
- COMM, IFR, MEL, SEL
On my CubCrafters FX-3 the POH says bottom of the green arc is 55 psi. On my last FX-3 (2021) I never saw oil in the yellow. On my new FX-3 it's caught my attention on the ground with lower RPM going into the yellow much less the bottom of the green on the new plane is 60 and not 55. Is this an error or was the prior plane an error on the green band? Had @craig.roser check his and his is set at 55 psi.
Rather than reaching out to CubCrafters I decided to just google the IO-360 oil limits. Good info found, seems like 60 psi is the correct number for normal ops, i.e. flying or 1000 rpm and above, whatever normal ops is. What was comforting to see is that it can go down to 25 psi at idle. IMHO CubCrafters sets the idle RPM too low, yes, we can adjust it, but if you pull the throttle full aft on the ground check your oil pressure, it can drop pretty good. Mine is hovering around 55 psi at around 700-800 RPM. I need to pull the throttle full aft and leave it there for a check, I'm afraid the engine won't continue to run at this position and need to verify.
Still hyper sensitive to the new plane checking everything very very carefully. This may be one downside of buying a new plane, having to be on edge non stop waiting for something while a plane with 1000 hours + (or two turbofans and an ejection seat) you just go fly!
Good article nonetheless:
www.kitplanes.com
Rather than reaching out to CubCrafters I decided to just google the IO-360 oil limits. Good info found, seems like 60 psi is the correct number for normal ops, i.e. flying or 1000 rpm and above, whatever normal ops is. What was comforting to see is that it can go down to 25 psi at idle. IMHO CubCrafters sets the idle RPM too low, yes, we can adjust it, but if you pull the throttle full aft on the ground check your oil pressure, it can drop pretty good. Mine is hovering around 55 psi at around 700-800 RPM. I need to pull the throttle full aft and leave it there for a check, I'm afraid the engine won't continue to run at this position and need to verify.
Still hyper sensitive to the new plane checking everything very very carefully. This may be one downside of buying a new plane, having to be on edge non stop waiting for something while a plane with 1000 hours + (or two turbofans and an ejection seat) you just go fly!
Good article nonetheless:

Maintenance Matters
Oil pressure is always a concern to anyone who flies a powered plane. Everyone knows that if your oil pressure drops to zero, your flight will be ending soon, whether you want it to or not. But there is much to understand about oil pressure beyond knowing you need some. In this article we’ll...
