Sea Ray

I have not examined it yet and wil dlo do so soon. But did you mean that the line should be downhill from the tank (assume
top) to the vent? I filled the tanks today and had little spillage. The only thing I did differently was to leave the fill
caps off while waiting my turn for fuel.

No, the vent should be higher than the tank.

I have the same issue with the starboard tank on my newly purchased 1996 440 Express Bridge. Also the fuel backs up and spits out the fill when I stop filling. Have checked and cleaned out the vent for stoppages and blew out the tank vent hose to insure no stoppages. That helped a little but still have the issue. When I blew out the tank vent hose it felt like I was blowing into the fuel. Is that normal? I assumed that the vent was at the top of the tank and the only time there would be fuel is when the tank was full. Will check the routing when get back to boat.

Please help - hate fuel in water if it can be helped and using up a lot of oil cloths when filling.

That is an indication of a obstruction in the vent line.

I have a 2002 460 as well with the same issue, but not as bad and it happens on the port tank. Starboard takes fuel at a high rate and clicks off. On the port side we have to ease up considerably and as a consequence, I always use a "burp" bottle over the fuel vent on the port side. I will however take a look at the vent line plumbing because there are no other obstructions.

Some models, the 460DA, 440EB,450EB, 450DA, among others, have the fuel deck fill plate located at about the same elevation as the entry to the tanks at the other end of the fuel fill hose. Diesel fuel foams as it fills so the propensity is to be adding fuel at a faster rate than the foam bubbles can dissipate and you may get a spill out of the fuel vent or even out of the fill deck plate.

Since this is a product of the boat's design, there isn't anything to fix, but you can do some things to avoid the spills: learn the sound of filling the tanks.....when the foam gets to the tank inlet, the sound changes, so slow down or stop and let the foam dissipate; just slow down; there is a whistle you can get for the vent line that stops sounding when the tanks vent gets close to full (these things are irritatingly loud and you might draw a bunch of looky-lou's when you use one; Parker has offered a fuel return valve for the vent line that prevents overflows. You should also check your vent lines to be sure they are clear and run consistently up-hill to t he vent fitting or that they have a spot in the ose near the outlet secured above both the tank outlet and the vent fitting on the side of the hull.

Great explanation. I always estimate the amount of fuel needed and slow considerably in the final 10-15 gallons, always listening for the change in sound as it fills. I am so much better at this than some of the fuel assistants that I insist on filling the affected side myself and using the overflow bottle. (I will stop filling for example if another boat is idling by during that critical time when I cannot hear the sound.) However I will check the vent plumbing on that side as you suggest and ensure that it is "uphill". Thank you Mr. W.

This will SOLVE your problem.

https://www.parker.com/literature/Racor/Racor_Fuel_Filtration_-_LifeGuard_Fuel-Air-Separators_-_RSL0184.pdf

Thanks Captain Rick...sounds like a really good solution.

I just temporarily duck tape cutoff milk jug under it. Specially when topping off for long trip.

I stumbled on an unlikely solution. I have been opening both fills when refueling and have not spilled a drop!

I did two things to help the port side vent from dripping during fueling.... I straightened the vent line and turned the shop vac into a blower and placing it over the vent to blow back any fuel that had collected in the low spots back into the tank. So far, so good...