Blue gas from fuel filter

[trobinson017]

Hi all,

I have one of those see-thru fuel filters with the replaceable filter cartridge on my Johnson 130 Oceanpro which I replaced today. I disconnected the engine side (output) and poured the gas out into a glass container. The gas that came out was blue! I mean like, really blue. It did not look blue when viewed thru the glass body of the filter before I removed the output hose. After draining the blue gas from the filter I pumped the primer bulb a few times and that gas came out looking normal. Also, I had just removed and emptied my fuel/water separator and that gas was normal colored also. The only thing I've changed recently was the fuel hose from separator to bulb and bulb to fuel filter. So could it have been the rubber gaskets in the fuel filter ends? They looked in great shape to me, not like they were dissolving. Maybe the new hose segments or primer bulb? What else could cause 1/3 cup of gas to turn blue?

As always, TIA!!!

Troll

 

[NelsonQ]

Re: Blue gas from fuel filter

The fuel before the engine side is clear fuel color. Afterwards, pre-engine its blue.

To me it sounds like you have an OMS system (automatic oil mix system) on your boat. Older Johnson's have a VRO or VRO2 oil mixing system. OMS is a newer version of it and I believe being a 130 HP, your motor is late 90s early 2000s (guessing here)

This is normal. Once the fuel passes thru the filter, it is mixed with oil (where the blue colored oil turns it blue).

I'd assume the fuel you're referring to is in the hose after the OMS pump.

Sounds perfectly normal.

If its before the pump, may be a leak in the hose between filter and pump drawing oil back in the line. (I'd don't think that would be normal to draw backwards into the fuel line)

Again, this is my understanding of how it should be setup but hopefully one of the other experts can confirm or elaborate.

 

[trobinson017]

Re: Blue gas from fuel filter

Thanks NelsonQ, I do indeed have an oil injection system. But I believe the injector is after the fuel filter (not certain). So I'm guessing that when I removed the fuel/water separator canister that , maybe, it caused a reverse suction, pulling mixed fuel back into the fuel filter. But I agree the blue color is due to the oil mix. D'oh! I'm not going to worry about it for now.

Thanks again!

Troll

 

[NelsonQ]

Re: Blue gas from fuel filter

So it is between the filter and the injection system.

I suspect perhaps a leak. I don't know if the line/primer bulb change you made if there is a leak in that line would it create a reverse flow/suction pulling the oil backwards into the fuel line but is most likely considering it happened after the fuel line changes. Since they're new, most likely around the end connections.

 

[jwbmarine]

Re: Blue gas from fuel filter

thats kind of a confusing post--but here is some info,that may help you---

First----if your filter,is BEFORE the pump,as it should be,and u see blue gas in it...........there are only THREE things that can cause this!!!!

1.bad VRO/OMS pump
2. Pressurized oil tank
3. both

 

[trobinson017]

Re: Blue gas from fuel filter

thats kind of a confusing post--but here is some info,that may help you---

First----if your filter,is BEFORE the pump,as it should be,and u see blue gas in it...........there are only THREE things that can cause this!!!!

1.bad VRO/OMS pump
2. Pressurized oil tank
3. both

I guess to clear up confusion I should describe in brief the fuel line arrangement up to where it connects to the engine block.

Fuel line from gas tank goes to fuel/water separator mounted on the side wall of the transom. From there the fuel line goes to the priming bulb, both were recently replaced. From priming bulb to fuel filter which is just on the other side of the engine cowling. This line was also recently replaced. From the filter it goes to the engine, not sure what it's connecting to at that point. The blue gas came from the filter. After removing the filter I could squeeze the priming bulb and that gas came out normal coloring.

So I guess the VRO/OMS pump is what pumps the oil from the oil tank into the gas line? if that's going bad then I should replace it asap. Last thing I want is a seized engine. But how can I tell if that's actually the problem? Not sure how to tell if the oil tank is pressurized. Can I bleed air from it somehow? It's a small tank inside the bilge area with the batteries.

I'll run out and take some pics of the whole shebang and post them in a few minutes.

Troll

 

[trobinson017]

Pics

Pics

Here are some pics of the fuel line arrangement and the oil tank. I have to submit them one at a time due to size.

 

[trobinson017]

Re: Blue gas from fuel filter

Oh yeah, I've annotated them to make it easier to follow along.

 

[trobinson017]

More pics

More pics

Oil tank pics

 

[NelsonQ]

Re: Blue gas from fuel filter

Not sure how to tell if the oil tank is pressurized. Can I bleed air from it somehow? It's a small tank inside the bilge area with the batteries.
Troll

Is the primer bulb on the line from the oil tank solid?

Also, did if you pull the line in front of the filter again since changing it? Do you get the same results of the blue fuel? The reason I ask is you could've had a leak in the lines that you've since replaced when you did the filter. It make have created a situation sucking oil back into the fuel line.

If you remove it, and its not there, you may have resolved the issue unknowingly.