Follow Up to earlier post - Oil in High Pressure Fuel Pump

[tjo716]

So I tried one more thing. I replaced part of the fuel line (post low pressure fuel pump) with clear tubing to see if the fuel was picking up any oil from the fuel pump. As you can see in the pic, the fuel is clear after the LP pump. I cranked it to get the fuel moving and it actually started. I turned it off after 2-3 secs. I then drained the VST and the fuel came out dark as before. What could possibly be doing this ???? start.jpg

[redlowrey]

When i read your first post it sounded like you vst is full and over flowing into the crankcase line that comes off the top of the vst, that is probably why it is stalling, pull it off and have a look you will probably see the oil in the pipe.
Drain some fuel out of the vst and it will run normal till it fills up and over flows again.

[Moonlighter]

When i read your first post it sounded like you vst is full and over flowing into the crankcase line that comes off the top of the vst, that is probably why it is stalling, pull it off and have a look you will probably see the oil in the pipe.
Drain some fuel out of the vst and it will run normal till it fills up and over flows again.

Red, this may be a stupid question, but is there ANY way that oil could be being pushed back into the VST thru that vent line that goes to the crankcase? Seems really unlikely but just wondered if it could even be possible?

[redlowrey]

Red, this may be a stupid question, but is there ANY way that oil could be being pushed back into the VST thru that vent line that goes to the crankcase? Seems really unlikely but just wondered if it could even be possible?

I agree, normally if the vst filled up it would be sucked into the engine and dilute with the engine oil and over fill the crankcase, or late engine through the purge valve. I was thinking high crank case pressure blowing back, and wait for a response tomorrow to see whether there was oil in the line and go from there.

[tjo716]

Red and Moonlighter...thanks for the input ...much appreciated.

Update- So yesterday I put muffs on it, ran fresh gas out of a can treat with Seafoam, and she started right up. For the first minute she was idling somewhat rough and then smoothed out. I ran it 10 minutes at different rpms. She would hesitate a bit upon acceleration but otherwise seemed "back to normal"

To address your thoughts I have attached some pics and offer this info (hope it helps).

Red- You stated "Drain some fuel out of the vst and it will run normal till it fills up and over flows again."...........My question is why would would it overflow and why is it a dark color,?


ALso, which "pipe" or line should I check for oil?


Thanks !!!
IMG_8786.jpg

Here is text from the tech manual...FUEL DELIVERY SYSTEM COMPONENTS The fuel delivery system is composed of the low pressure fuel line components (fuel tank, filter, pump etc.), fuel vapor separator, high pressure fuel pump, high pressure fuel filter, fuel pressure regulator (located in the fuel vapor separator), delivery pipe, fuel injector and hoses. Fuel is supplied through the primer bulb, low pressure fuel filter, and low pressure fuel pump to the fuel vapor separator. Fuel flow from the fuel vapor separator is pressurized by the high pressure fuel pump and supplied through the high pressure fuel filter and fuel delivery pipe to the fuel injectors. The pressure regulator maintains fuel pressure in the feed line between the high pressure fuel pump and fuel injector. This pressure, maintained at a constant level, is higher than the pressure in the vapor separator chamber. When fuel feed line pressure exceeds vapor separator chamber pressure by more than approx. 250 kPa (2.55 kg/cm2 , 36.3 psi), the valve in the fuel pressure regulator will open and return the excess fuel to the vapor separator chamber. Pressurized fuel enters into the intake ports through the fuel injector based on the sequential signals supplied from the ECM. IMG_8754 (1).jpgHP Fuel PUmp.jpgfuel.jpgIMG_8796.jpg

[redlowrey]

Mate if the needle and seat does not hold fuel will keep rising till it over flows out of the vent line on top of the vst into the engine.
Pull the vent line off the vst and have alook to see if there is oil in it.

[Harper]

See my post #7 in this thread with the same problem .. https://www.suzukioutboardforum.com/...50-oil-in-fuel

[tjo716]

Thanks Harper (and others).

Update..... I pumped fuel (fresh from a separate gas can) through the system several times and saw that the VST drainage was getting less dark. SInce it started earlier, I decided to take it out and run it. I primed it with the fresh gas from the can and then connected the hose back onto the tank in the boat. I ran it for 20 minutes at all speeds and WOT. Acceleration was as good as ever. She ran beautifully (like there was never a problem).

So, in short, the problem has fixed itself. I went ahead and brought it into a mechanic to give everything a good look. There is still the question of where the oil deposits on the transom came from.

Will update when I get mechanics feedback

Thanks

[redlowrey]

Mate you don’t understand what is going on inside your vst, fuel is gradually rising and won’t make any difference how the motor runs till it over flows out of the evap line into the engine, and you will only notice it at low rpm or idle.

When you run at high rpm it will lower the level back to where it should be, the hole saga depends on How much extra fuel gets past the needle and seat over time. HOW MUCH EXTRA FUEL OVER TIME.

[tjo716]

Thanks Redlowrey and sorry , I don't understand what you mean by HOW MUCH EXTRA FUEL OVER TIME. Could you please elaborate?

Thanks !