Can (does) OMC Pressure Tank System contaminate fuel?

[SeaKaye12]

Hi....

Found a little time to work on the '55 Fastwin. After running for a bit in the test tank, I un-plugged the dual-hose gas line in order to allow the carb to run dry.

I noticed black fluid dripping from the pressure side of the quick-connect on the engine.

Is this carbon contaminated fuel from the crank-case? Whatever is is...will it run through the hose and contaminate the fuel in the tank?

Thanks, Chuck

 

[nwcove]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

are the fuel lines old? they have a tendancy to break down and let black rubber crud go through the system. my 57 5.5 drips fuel oil mix back through the pressure line tho, but its never caused any issue, not black fluid, just foamy gas/oil. ( if the motor hasnt run for years, it could just be "cleaning itself up".

 

[boobie]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

Sounds like you have some fuel/air line deterioration.

 

[Steve A W]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

How are the "O" rings in the coupler?

 

[F_R]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

The fuel/oil/air blowing out of the air line is coming from the crankcase. The crankcase should be clean inside (no carbon). If the hose is disintegrating inside, it certainly needs to be replaced.

 

[Chris1956]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

I used to recycle the excess fuel that puddled in the crankcase of my old Fat-Fifty, rather than dump it overboard. However, I found it contained some water, mixed with the gas and oil. The motor ran fine on new fuel, but the recycled stuff was hard to burn up.

 

[kbait]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

Change out twin-line hose and coupler orings (use omc/brp replacements. Sierra aftermarket's are larger and about impossible to install from the plug end. I found this in an old post:


TO REMOVE O RINGS: Use your straight tool to depress plunger in connector. Insert the hooked tool "flat" under the o ring, twist it "up" to catch the oring, then quickly pull it out from its seat.

TO REPLACE O RINGS: Put some oil on oring and place it on the connector plate. Depress the plunger with the straight tool by pushing it through the center of the o ring. Pinch the o ring together with your fingers and gently stuff it into position in its seat. Use the straight tool to position the o ring positively by pressing against the inside of the oring and moving the tool in a circular motion around the connector opening.

Check them for leaks, if they dont leak you are ready to use.


-W/new line and orings, you should be good!

 

[F_R]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

I used to recycle the excess fuel that puddled in the crankcase of my old Fat-Fifty, rather than dump it overboard. However, I found it contained some water, mixed with the gas and oil. The motor ran fine on new fuel, but the recycled stuff was hard to burn up.

Water from the crankcase??? Extremely bad news. I assume you don't have the motor any more?

 

[Chris1956]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

No, I got rid of it. The water never seemed to be an issue. The motor always ran well. I got tired of the fuel consumption (mostly the 1/3 unburnt fuel), the slow speed, and the requirement to clean the carb every year, and reset the high speed mixture adjustment

 

[1946Zephyr]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

sounds like a bad lower crank seal, if water is coming out with the gas.

 

[nwcove]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

its easy to test for water exiting the air/pressure line, gravity feed the motorwith a single line, and put the air line ( removed from connector of course) in a clear container, run the motor in a barrel, catch the drips from the air line and let it settle overnight.

 

[Chris1956]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

Real easy to detect the water. I was using red 2 cycle oil at a 24::1 mix. The stuff out of the crankcase looked like italian "Vodka Pasta" sauce, or Bolognese sause. very pink......

 

[SeaKaye12]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

hehe...the discussion has gotten real interesting, as questions here often times do. Sounds like some of us need to run water separators in our pressure lines

Yesterday I replaced the short hose from the block to the coupler; expecting to find it mushy and ugly inside. It wasn't. Looked new.

As for the condition of the supply hose and o-rings...they look fine to me ...and since the color of the fuel going into the glass filter bowl on the carburetor looks pure....I don't see how that would be causing what I'm seeing anyway. Unless of course that I'm missing something.

The black fluid that dripped from the coupler looked much like graphite lock lube....

Thanks for all the interest,

Chuck

 

[Chris1956]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

Chuck, Just so you know, the Fat-Fifty had a fuel pump and a single fuel line. I was collecting all the fuel that build up in the crankcase, so it wouldn't get dumped overboard, per the design of the fuel recirculation system on thta motor. I believe it is relevent to your question, because the crankcase pressure I discuss is the same that feeds your pressurized fuel tank.

I wished I would have thought of putting a water seperator on my fuel recycling system. I might have kept the motor longer.

 

[SeaKaye12]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

Chirs1956....it is relevant and interesting. So; the pressure that you speak of ....is that just blow-by gasses from combustion? If not...where does it come from....and what regulates it?

Chuck

 

[Chris1956]

Re: Can (does) OMC Pressure Tank System contaminate fuel?

Chuck, The Fat-fifty had a drain on the bottom of the intake manifold. There was a passage from the crankcase to the intake manifold. Everytime the piston went down it created pressure in the crankcase which blew out any accumulated fuel (and water) in the manifold and quite a bit of good fuel/air mix. All of this went thru a hose into the waterjacket and then into the lake. I disconnected the hose from the waterjacket and ran it into a vented container mounted under the cowl, near the carb intakes. All the good fuel/air vapor was sucked into the motor and reburned. All the liquid gasoline and oil (and water) gravity fed back to a fuel tank in the boat. I would mix it with fresh fuel and reburn it.

Your pressurized fuel system is pressurized by the same downward motion of a piston, thru a reed valve.