SN: 0B169682
1986 Mercury 175 HP Blackmax
After sitting for extended period, noticed oil is backing up in the fuel supply line. Guessing the fuel line had as much as 4 ounces in there.
Been researching on this forum and am guessing I have a faulty check valve. Evidently there is a check valve that allows air to enter the block oil tank if the remote tank becomes plugged (to prevent the tank from pulling a vacuum) AND bleeds off pressure in the system when the outboard is shutdown. I suspect this check valve is my problem. Is the correct part number for this check valve 42425 4?
Do you think the above check valve is probably the problem?
Curious, isn't there a check valve in the primer bulb that would prevent the oil from backing up in the fuel supply line? Why didn't this stop the oil from backing up?
Curious, how does 42425 4 work to relieve pressure on shut down. Does it constantly bleed a little pressure? If not, what causes it to bleed pressure only at engine shut down?
Thanks for much for the help,
Ron Maxwell