2003 Evinrude 175 using twice the oil as other motor

[bosts1]

Hi guys, i just found this forum and thought it would be a good starting place. I have a CC with twin 2003 175 Evinrudes. My starboard engine is using twice as much oil as my port engine. I notice it smokes more when revved in reverse and I notice oil leaking out of mid engine cowling(not a whole lot but definately leaking). I topped both oil tanks off this weekend to test. After the weekend the starboard engine tank is empty and the port tank is over half full!
I had a mechanic check it out and he said he tested the oil system and its working fine. He replaced an o ring that was leaking oil, but the problem is still here. I have tested the return line and when I squeeze the bulb it puts oil back into the tank.
Has anyone had this issue, or have any advice on where to begin other than finding a new mechanic! Obviously the one I used isn't good. I'm new to the Evinrudes. I should say the engine runs like a top its just wasting that precious XD100! Thanks in advance,
Stanton

[Joe Reeves]

Usually caused by a failing VRO. However............

A fuel restriction would force the VRO to draw more oil than usual. Check the anti siphon valve, located where the flexible fuel line meet the fuel tank fitting.

(Fuel Anti Siphon Valve)
(J. Reeves)

Many of the later OMC V/6 engines incorporate a fuel restriction warning via a vacuum device attached to the powerhead. If the engine overheats, or if you have a fuel restriction, the warning is the same.... a steady constant beep.

NOTE... Only the V/6 & V/8 engines have the above "Fuel Restriction Warning". The warning horn will not sound on the other models.

The fact that a engine is not overheating, but the warning horn sounds off with a constant steady beep, and that the rpms drop drastically would indicate that the engine is starving for fuel due to a fuel restriction. Check the built in fuel tank where the rubber fuel line attaches to the tank fitting. That fitting is in all probability a "Anti Siphon" valve which is notorious for sticking in a semi closed position. It will be aluminum, about 2" long, and the insides of it will consist of a spring, a ball, and a ball seat. If this valve exists, remove it, knock out those inner components which will convert it to a straight through fitting, then re-install it. Hopefully that cures the problem.

The above procedure will cure a restriction problem with the anti siphon valve as stated. BUT, it may also allow fuel to drain backwards to the fuel tank when the engine is not running (siphoning backwards) due to the fact that the carburetors/fuel pump etc are higher than the fuel tank. This condition is not an absolute as the valves in the fuel primer bulb usually prevent this backwards siphoning problem. However.... if this does take place, the cure would be to install a new anti siphon valve.

NOTE: There has been cases when the output valve in the fuel primer bulb would come apart, and the inner portion of the valve would actually reverse itself and be drawn back into the primer bulb's output valve body. This in effect would create a shut off valve and result in a fuel restriction. If this is the case, you should be able to feel something laying in the bottom of the primer bulb when held horizontally.