Mercury oil line plumbing

[Nathan R]

I have a mercury optimax 150 that I am putting on a Lund Tyee. The boat had a mercury motor on it previously so it has been a fairly simple instalation so far. My problem now is figuring out where the oil lines hook up. There is what appears to be an oil line that comes off the right side (facing forward in the boat), but there is an oil reservoir on the left side with hose and a brass "t" junction. One side of the "t" hasa hose that has been cut off and plugged with a bolt. The other side is a blank hose barb that points straight down. So if one of you guys can point me toward a schematic or tell me what I need to do I would really appreciate it. Thanks Oh and is there a proper method for priming /purging the oil system?

 

[Nathan R]

Here's a picture of the left side by the oil reservoir. I assume that one side of that T Junction hooks up to the oil supply line. What does the other side hook up to?

 

[Nathan R]

And can anyone tell me what this hose is for? It matches up with a hose that was on the boat already so that's what I hooked it up to. (I know it's not an oil line)

 

[Texasmark]

Pic 1. how about an onboard (the boat) oil reservoir? On the smaller engines like my 90 the oil tank is large and engine mounted. On the larger engines recalling my sons 150 earlier model, he had a small one on the engine and a larger one in the boat.

Pic 2. Speedometer hose. Merc uses a hole in the front edge of the lower unit for water pickup to run the speedometer. Nice as it saves the mess of having a boat mounted one.

Mark

 

[Nathan R]

Thanks for the reply. Yes, pic 1 is the onboard oil reservoir. Somehow I am suppose to hook up the separate 3 gallon oil tank via rubber hoses. I think I have everything figured out except for the T Junction in pic 1. Thanks for the info on pic 2. I was wondering where the speedo was going to get its information from.

 

[sam am I]

As pictured(Pic #1), one of the two unconnected(the one w cut hose or un-used blank barb)fittings has a check valve inside to allow air in at a cracking pressure of around 4 PSI(prevents vacuum from forming in reserve tank should the remote tank oil feed hose get pinched off, or gets cut off and a BOLT happens to plug it!!

That reserve tank has a air tight cap, as oil is used up(sucked out), air needs to get in else you could starve the pump(motor) of oil with a vacuum forming in the tank!

The check valve port/barb of the "T" just mentioned in some typical configs(yours looks fine as is), has just a open ended/vented piece of hose connected to it and typically points downwards(like yours to keeps the crap out). The other port/barb then of the "T" will go to the oil feed line(not air pressure line in the case of Oil Injection System) of the pressurized "remote" oil tank.

By the looks of the shape of the "T", orientation and w the bolt, the blank/un-used barb obviously appears to be the check valve air intake vent. Notice the extended shoulder.

 

[Nathan R]

Awesome! That was my assumption, but we all know what happens when we assume things. If I don't get the lines hooked up right it will use the oil in the motor reservoir, right? I'm not going to blow it up right away if it's not getting oil from the separate oil tank.

 

[sam am I]

.........

 

[sam am I]

Awesome! That was my assumption, but we all know what happens when we assume things. If I don't get the lines hooked up right it will use the oil in the motor reservoir, right? I'm not going to blow it up right away if it's not getting oil from the separate oil tank.

They're designed to be able to run strictly off the reserve tank for a short while (30 or 40 minutes I think at WOT). ****Yes, it can be ran as is but, it depends on what you mean by "right". Obviously again, just don't allow the check valve vent port to get blocked. Looks like it snaps into some grips on the side of the tank to keep it safely breathing.

****BUT!!! Be aware, if you continue to run "as is" it's running on "limits".e.g., The norm operation does not use the check valve to allow air in as oil is used, the norm is to replace emptied oil space w more oil from the remote tank.The venting process of allowing air in the reserve tank, is a "backup" in the event of a remote tank failure. Your last stop gap running like this is the alarm sounding when the reserve tank goes empty. Then POOF!!!*******