2007 DF150 Strong Fuel Smell. With evidence of fuel coming out of exhaust

[satellite]

I was wondering if anyone had insight on this. Two things happened that caused a little concern. I was putting fuel in my tank this weekend and noticed a little condensation on the fuel cap. Never seen that before. About two hours into trip when at motor was turn off, I noticed a very strong fuel smell. Stronger than usual. Then on the return to the ramp, I noticed little bits of fuel coming out of the exhaust hole below cowling when if pulled into the doc. I did some searching on this, and read a post where it was suggested the needle valve on the VST could be stuck due to too much moisture. Does anyone have any experience with this? The motor seemed to run without issue. I did add a container of sea foam before the last time I put fuel in the tank. Hopefully that didn't screw things up. About 30 gallons ago. I should also note that I have never put ethanol fuel in the boat in the four years I have owned it. Neither did the owner before me. So I am curious where the condensation in the tank came from.
Thanks for any help or suggestions. Mark

[Harper]

Metal tank? or plastic? Located in a humid environment during these cool months? Boat tanks are open to the atmosphere, unlike modern autos. Humid air will condense on the inside of the tank, which is one reason you're so much better off using non-ethanol gas. So you're ahead of the game there. Metal tanks will be more conducive to condensation also. Don't know how much fuel you keep in your boat, but keeping it topped off helps to mitigate the condensation problem. I always keep my 60 gallon tank full in the cooler winter months, or nearly so. I boat year-round. But where I keep it on the trailer does freeze regularly.

As to the fuel smell and the emissions from the exhaust port, I don't have many ideas on that. But can't see that it would be due to an overflowing VST tank. That would come out the vent tube in the front of the engine. Are you sure it's fuel spraying out? My DF150 doesn't ever have any visible exhaust coming out that auxiliary exhaust port.

[satellite]

Thanks for your reply. I have a plastic tank and it has been really cool the last few weeks. With one big rain event. In which I did have to drain a good bit of water out of the hull. Left the plug in. Since i live in southwest Florida, I don’t experience freezing temps very often but our humidity level is relatively high. That could explain the condensation I saw in the fuel cap.i will change out the fuel separator filter this weekend to see if ther is any water in it. Hoping I can find where the leak maybe coming from or if its possibly related to vst overflow. It was definitely showing evidence of fuel coming out of the exhaust port while at the doc. It was not a lot, but enough to cause concern. I will also try to replicate this with the boat on the trailer. Thanks again.

[Harper]

Keep us posted on your findings.

[Murray]

I doubt very much Seafoam would cause any grief. I had a Ford 150 that had a fuel pressure regulator issue where 60psi fuel pressure was being fed to the injectors and as a result my crankcase oil had a fuel smell to it. If memory serves the Ford was throwing an O2 code. Never noticed a fuel smell at the exhaust but I never checked. Was told that the excess fuel was leaking through the pistons rings and into the crank oil. I have had fuel in the exhaust in a lawnmower when I flooded the engine. Is it possible that your fuel is overflowing from the VST and running down the inside of your lower unit cowl and escaping beside the exhaust. What do your plugs look like? Too much fuel/too little air would cause your engine to run rich???

[satellite]

Update on fuel leak. I have tried to replicate and find the leak. It would not show signs of leaking when I test ran the motor while on trailer in hopes that pressurizing the fuel system would show the leak. Also put the boat in the water for short trip, no visible signs leak. However yesterday had the boat in the water and this time the fuel smell was overwhelming. Again a very short trip. After putting boat back on the trailer and returning home. I took the cowling off to see if I could find visible signs of fuel. I think I may have found the leak. Well at least I hope this is it. I have attached a photo of the connection just above the low pressure fuel pump. It looks as thought the hose was not completely seated. Somehow produced a space between the hose and the pump. There was visible fuel on the pump. Wondering if I should go ahead and replace these fuel lines and clamps? Thank you everyone for your input. IMG_20190316_210454467.jpg

[Murray]

For the cost of clamps and fuel line I would replace, at least the one you think is leaking. By doing so you will eliminate one potential source for a leak. Once you get the culprit off you will be able to judge the condition of your fuel lines and decide if they all need replacing or just the suspect fuel line. If you do replace all the lines do one at a time, you can use the original as a sizing guide.(length)

[satellite]

Update again. I just refastened the hoses, and pressurized the fuel system. Found that it is leaking out of the low pressure fuel pump itself. Guessing it needs replacing unless this happens with bad gasket. IMG_20190323_182217_01.jpg

[satellite]

May need some professional help on this one. In order to replace this pump, the manual says I need to rotate the crankshaft so that piston number 1 (top cylinder is top dead center on compression stroke.) does anyone know if this is difficult? Thanks for all of your help.
Mark

[catacom225]

The Pump is cam driven , so there just saying to have the cam lobe on the short stroke or side, so when installing the new one there will be less resistance , basically?

[Harper]

Catacom225 is correct. It's easier to replace the pump with the cam lobe on its low spot. But I've pulled the pump on my DF150 before without regard to the position of the cam, and it's not difficult at all to put it back in. If you're on the high side of the cam, you'll feel the spring pressure of the diaphram spring as you seat the pump. Just make sure you press it in evenly and tighten the bolts alternatively to keep the pump straight as it goes in.

[satellite]

Thanks for all,of your help. I’m hoping I can visualize what you’re saying. I created another post called fuel pump top dead center in hopes there was a video online to demonstrate. But I went ahead and bought the parts just now. My local parts place wanted $180 and boats.net sold for $144. So I ordered from them. I will try to record the install and post on YouTube.

[satellite]

Everything replaced and works. Thanks for everyone's help. One person that has helped me immensely on the boat over the last few years gave me a warning on using sea foam. Is it possible sea foam could have potentially affected the diaphragm inside of the fuel pump? I have the old one on my work bench. I am thinking of dis-assembling to see what the diaphragm looks like.

[Harper]

Please do that and let us know. I would not have thought that SeaFoam would ahrm anything, but that diaphram might just be the exception.

[Murray]

Please do that and let us know. I would not have thought that SeaFoam would ahrm anything, but that diaphram might just be the exception.

I agree, I’ve been using Seafoam for decades and have never had any issues that are related to Seafoam, as far as I’m aware of.