DF175 - Gasoline in Oil (Crankcase)

[tudunka]

Went fishing over the weekend and the oil light came on. I trolled back to dock and checked the oil and I have gasoline leaking into my Oil crankcase. What would be causing this?

[Moonlighter]

First thing to check is VST float level. Or blockage in VST. Either will cause excess fuel to run into crankcase via VST vent hose.

I am told an easy way to check is to remove VST vent hose from where it runs back into the block and start the engine, allow to run for a while, if fuel drips from the hose, you have confirmed the cause and know what needs to be done to fix it.

[tudunka]

Moonlighter - the unit is a 2006 and the VST has never been serviced. Would it just be best to order a new assembly and not have to mess with the float, fuel pump....ect ?

If I do order a new unit, is it just plug-n-play ?

[tsturm]

Yup, plug & play. Change the L/P & H/P filters & change or install a water separator also

[tudunka]

Okay, I have already put on a new Low Pressure Filter, but I can't find the High Pressure (H/P) filter for my DF175. Where would I find a diagram for this?

[tsturm]

Between the lp pump & the vst. on my 2012 it sits above the vst

[Harper]

High pressure filter is just above the VST connected to the VST outlet by a hose. I understand that it's also it's possible that the fuel can leak through the diaphram of your low pressure fuel pump into the crankcase.

[tudunka]

As for the low pressure fuel pump diaphragm, that was originally what the OB shop changed out. So, it happens again and I go back to ask them and they suggested it’s probably the VST..

Let me share some information to any of you who may experience this. So last night I went to drain the crankcase that is now full of gasoline/oil and as I was about to remove the drain plug I recalled the shop tech saying he drained what he called a few gallons out of my crankcase, so with this in mind I made sure I had enough containers around me to catch the fluid, I had my funnel, gloves on, paper towels.... everything was in place n I was ready..... so I pull the plug and the force of the gas/oil coming out was more than I expected .... it overflowed my funnel.....it was like a freakin firehouse......it was flying everywhere....... what seemed like an eternity... really it was like 3 seconds..... I was covered in gas, the floor and anything else around me was just soaking in this shit..... it was like one of those Oh F....... moments!

Needless to say, I got it all drained, and I filled a 12qt and another container close to 15qt...... I needed a beer after that!

[Moonlighter]

VST should be easy enough for the shop to clean out and reset float level properly without buying a new one. Assuming that corrosion hasnt set in in there.

Its a really good idea to tell us what has been done already in an attempt to find and solve the problem. That way, people dont waste their time suggesting things that have already been done. That news about the LP pump diagram falls into this category.

Are you running a separate inline water separating filter between the fuel tank and the engine? If not, it is essential to do so to help reduce contaminated fuel getting to expensive parts like VST’s. If you already have a RACOR style filter, have you changed the element? And drained it out to look for contaminants? Every 100 hrs you would want to change it, and if you see significant contamination, more frequent changes are a good idea until the contamination clears up (you could have got a bad load of fuel at a recent fill)

[tudunka]

Moonlighted, you’re probably right in that I should have mentioned earlier. I’ve had the OB for 13yrs now and 95% of its use has been mostly trolling hours at less than 900rpms (due to fishing), so it has not been abused.

i don’t have a water separator filter and not sure where to find one, but sounds like I should. The only ones I’ve seen are the ones for Diesel engines. Any you could recommend?

[Moonlighter]

RACOR are a well known brand and available pretty well worldwide. They come with a clear plastic bowl at the bottom and a drain plug so if you see water in there, you can open the drain plug to let it run out. There are numerous copies of their designs out there as well. Sierra are one of the more common ones.

http://ph.parker.com/au/en/marine-fuel-filter-spin-on

I have no idea where you are located, but any good marine chandlery or outboard dealer will stock such filters. Easy to fit, mostly in the transom area and most commonly fitted so that the primer bulb is in the fuel hose on the engine side of the filter.

I am not exaggerating when I say that these filters are absolutely essential for any outboard powered boat. Even more so for any efi engine, where clean fuel is essential and where blockages can cause significant damage to fuel system components. Yes, the engines do have their own low and high pressure filters but they are really the final line of defence and they are expensive to replace.

You have just found out why - it is too easy these days to pick up a load of contaminated fuel, and then you have the dangers and expense of a fuel system that is compromised.

[tsturm]

https://www.westmarine.com/buy/racor...64?recordNum=2

[tudunka]

RACOR Fuel Separator has been ordered. Also, someone suggested to me to make sure the VST has gas in it before starting. Won't priming with the Primer Bulb be enough or is there another step?

[Moonlighter]

When you turn the key to “ON the electronic fuel pump cycles for a few seconds. If you turn the key on and wait a few seconds until the pump stops, then turn off, and repeat a few times, I think the system will be primed up.

When you fit the RACOR, once the head is fitted and the hoses connected up, fit the plastic bowl to the filter, then fill the filter as close as practicable to full with fuel, then screw it onto the head unit. Only hand tighten. This makes priming the system with the primer bulb soooooo much easier!

[tudunka]

Great information and thank You. Is the primer bulb located before the Racor or after?