Help with 850 Mercury bleeder line

hereto

Seaman
Joined
Sep 25, 2009
Messages
60
Hi all,
I have a 1976 850 Mercury and am replacing the bleeder line. At each end of this line there is a brass fitting with a hose barb to which the line attaches. I have not been able to find any info on this bleeder line in either of the manuals I have. Questions I have are listed below.

1) Are both of these fittings check valves and do they function the same. I can blow air thru the
barbed end of one of the fittings but I cannot suck air back thru it. The other will let air flow in
either direction, so I don't know if it is also a check valve or just stuck.
2) If both fittings are functioning properly, which goes to the top and which goes to the bottom.

Thanks in advance for your help,
hereto
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,103
Re: Help with 850 Mercury bleeder line

The top brass fitting is open. The bottom brass fitting is one way, out of the block. Test and clean them, but don't switch them. The bleed line forces excess oil in the crankcase bottom up to the top main bearing.
 

hereto

Seaman
Joined
Sep 25, 2009
Messages
60
Re: Help with 850 Mercury bleeder line

Thanks for the help Chris1956.

hereto
 
Top