Fuel Starvation / Fuel Pump Vent Hose

Sorry for the long post, but need some help. Due to some health issues and moving/selling my home, my boat has been sitting idle in my garage for a few months. I usually pull it out and run it in the driveway every few weeks during our so called winter in Florida if I dont get out much, but this time it sat longer than I would have liked.

I pulled it out to run it yesterday and I could not get it to turn over. Checked the obvious stuff, gas in the tank, lanyard in the run position, ect. I primed it with the throttle a few times which has always worked in the past for the cold starts, but it wouldnt go. I took the air cover off and the carbs were dry...On the advice of a friend and long boating veteran, I added just a little bit of fuel directly to the intake to determine it was a fuel issue and not an ignition issue. It ran for a few seconds until the fuel burned and then stalled.

My initial thoughts are that the fuel gunked up the filter and or pump / lines from sitting... But, I opened the hatch again this morning and notice that the vent tube from the fuel pump was not connected to the fitting on the intake. I thought maybe that was causing a problem, so I pulled the end out and noticed it was scorched and melted. So, the question is whether it was like that before I tried starting the engine, or if it was the result of what I did yesterday? Either way, I need to have the fuel filter replaced and possibly more. I would attempt to do it myself, but the filter is on the bottom of the pump which is located at the bottom of the engine out of view, with about 9" of space to work. I guess I can try a mirror and flash light, but im a little uncomfortable messing with the fuel lines...I will change the oil and other easy stuff, but its a little out of my comfort zone.

Does anyone know where I can get a piece of the tubing? I checked west marine and didnt see anything. I was thinking grainger as well. (I think its called Tygon?). I also am concerned as to how/why it melted...anyone else ever see this? Lastly, as you will see in the pics, I am starting to get some rust on the engine block in a few areas. Is there a good solution besides cleaning with a wire brush and re-painting?

This pic shows the tube which connects to the small brass fitting to the right.


Here is the bottom side that is scorched....

That line is targon. It is a special high grade plastic. It is for safety. If your fuel pump diaphragm ruptures it flows fuel back to the carb to be burnt. Replace your fuel pump and the targon line! Dangerous situation.

I think your fuel pump may have a ruptured diaphragm. Perhaps a backfire caused the burnt line.

Thank you for the reply Quint. Could the fuel pump damage be directly from the fuel varnishing from sitting idle? Do you think the fuel pump replacement and vent line alone would solve the issue? I assume they check the pressure in the lines when they replace the pump? I was also worried about the old gas left in the tank.

I unfortunately witnessed a very bad boat explosion in person a few years ago, so I understand how dangerous fuel line / pump issues can be. I will leave leave this one to the professionals and get it looked at.

After removing the damaged drain tubing and getting a better look at it, the end that melted has taken the form of the engine block where it was wedged after it came off. Its almost totally flat. It seems more likely that the melted section could be from the tube coming off and melting on the hot engine block. That being said, it would have had to happen the last time I ran the boat since the engine never ran yesterday to get hot. Im wondering if there is a specific reason that the drain tube is clear plastic tubing vs. a black fuel hose. I know its a low pressure hose, but it concerns me that it came off in the first place. I went to West Marine and they didnt have the Targon tubing, but advised that I may want to use a piece of heat resistant fuel hose the same diameter and put a couple of clamps on each end to keep it from coming off. So, I did get a few feet of fuel hose and tubing and replaced the damaged tube. I still have the issue of the fuel pump to deal with, but I am wondering if there is a specific reason that mercury uses a clear plastic tubing for the drain hose, and if my fuel hose will be an acceptable solution.

Its a sight tube to be able to tell if it has fuel in it or not. If fuel is present, then there is a problem with the fuel pump. Should always be empty of fuel.

That hose is clear so that you can see if there is any fuel in it. if you see fuel in that line it means the fuel pump diaphragm is leaking. The hose as stated prior lets the fuel go to the engine and not into the bilge. The fuel pump should be replaced right away. That is the difference from a automotive pump and a marine pump.

Thanks, that makes sense. I figured there was a reason for the clear tube, but the west marine guy talked me in to the fuel hose option. I should have known better. I will plan on taking it in to get the fuel pump checked/replaced. I had not noticed any fuel in the line, but it has always showed some condensation (assume that was normal?). Im not sure where to purchase the Targon tubing to replace the damaged piece since that is an easy fix....I will check online, but does anyone have any suggestions?

The west marine guy steered you very wrong. I would educate him. As others said, the whole point of it being clear is so you can see fuel in it and recognize trouble (it should never have fuel in it!).
Go to a qualified marine service dept. to get replacement hose.

I will be sure to let the WM guy know too. Ill call around to the local marine service depts tomorrow for the correct tubing since they were all closed today. I appreciate all of the input and advice.