2004 Mercury EFI OB internal oil tank issue

[KenO250explorer]

Folks,   A few days,  the dash guage said "Reserve level 18%",  and the governor / guardian system kicked in limiting the revs.  I pulled the cowling and my internal oil tank (under the cowling),  was low and is not filling up  -   I had the motor running for 15 mins and the level didn't rise above 1/2 full.    I did take the cap off,  and saw the tank fill up,   but see no movement when the cap is on.      I have checked the connections from the fill to the external tank -   I see there are two lines going into the external tank,  one I assume is pressure from the motor,  the other feeds the internal tank.    I see what looks like a check valve in the line going to the internal tank, but not sure.    Any thoughts on how to troubleshoot / resolve this issue?

[Blue Agave]

Start the motor up, unscrew the cap on the oil reservoir under the cowling, when the oil reaches the top and starts to overflow quickly tighten the cap down. It's as easy as that, you probably ran the boat with the main oil reservoir empty and the motor pulled from the secondary tank under the cowling.

[KenO250explorer]

the external tank has been full the whole time -   so as this should be an automatic feed from the external to the internal,  I'm concerned it could be something else - check valve or two,  a leak in the air line that pressurizes the external tank etc.    Any additional thoughts?

[Blue Agave]

The external tank supplies the secondary tank and the secondary tank supplies the motor. Check both caps and seals on the external tank and make sure they are properly in place and air tight. Also, check at the bottom of the cap that has the two hoses on top, there is a filter on the bottom of the pickup that may be obstructed.  Are both hoses securely attached on the end of each hose. Does the external tank have a leak?

[GoneFission]

Sounds like the cap is not tight on the external tank or the line from the external tank is crimped.  The engine sends 2 psi to the external tank - that pressure sends the oil to the under-cowl tank on th engine.  So check out the cap on the external tank and the lines - probably will find it there.  

Good luck!

[KenO250explorer]

Gone Fission -  checked all connections -  seem tight and cannot see any kinks -   Q - in the schematic shown in the URL below - does anyone know if there is a check valve in the line from the external to the internal tank -  I.e. #40 or #15?  
Rationale is when I "flick" the connector (#40) with the engine running,  I see the tank fill up,  but when the engine is off and tilted,  the internal tank drains down to 1/2.   If we look @ the cost of the parts,  my bet is part #15 fitting for $29 has a check valve incorporated, but want to confirm with those smarter before I start swapping parts out.  

Thanks


http://www.boats.net/parts/search/Merc2 ... parts.html