Fuel tank vent question

[fox islander]

This might be a dumb question but I'll ask it. A leak in one of the seals of my racor stalled my engine the last time out. No problem, I sailed back. While waiting for the replacement cartrige to show up, I went to the archives and among other recommendations (tightened fuel line clamps, cleaned fuel pump screen, etc.), I checked to see if the tank vent was clear. I disconnected the vent hose and blew on it...sending a small amount of diesel out the vent. The vent is high in the stern locker as is the connection to the tank, making a low spot between the two. If theres diesel in that low spot does it need to be removed?

Thanks

 

[Don S/V ILLusion]

The vent line needs to be clear so it can vent, otherwise, you won't be pumping much fuel out of the tank before it starves the fuel pump. Just make sure to maintain the loop configuration to preclude getting water in the tank.

 

[fox islander]

What you say makes sense, so if you overfill the tank a bit fuel will block the vent. I typically try to squeeze as much in the tank as I can...I'll be rethinking that. Thanks.

 

[Anonymous 121765]

Fox,

I had the same problems years ago in my 1980 C30. The vent outlet on the stern was plenty high enough but I had the same sag in the line.

I especially had problems when fueling. The vent was always burping & this caused my fill tube to back up. You guessed it, fuel on my deck, and pouring down from the stern vent. Fueling was always a pain, using rags all over the place, & having to pour very slowly.

I used to fear fuel docks, and it was embarrassing watching the other boaters watching me fight the fuel spilling.

I fixed this by disconnecting the line @ the tank and slid PVC pipe down the hose up to the vent fitting on the stern. I had enough slack in the hose that allowed me to attach the pipe at both ends with the hose exiting down to the tank vent.

This way, coming off the tank, the hose rises vertically and enters the PVC which is bolted to the underside of the quarterberth about a foot aft of the tank. The trick for the aft support is to shimmy around the fuel tank to mount pipe clamp. Get as far back as possible to the stern vent.

If you use sch. 80 PVC, you shouldn't have to worry about the pipe itself sagging as the aft clamp may be located several feet forward of the stern fitting.

Hope this makes sense pal……….

CR

 

[Anonymous 121765]

Fox,

As a followup, since we are talking fuel, here are a few other things I did.

I haven't been to a fuel dock in years. I have a 22 GAL. tank and buy my fuel from a Shell station. The diesel fuel I get is filtered as good as Jet-A, and is as clear as water.

I cleaned my tank, cut an acess plate and redid my whole fuel system. When done, I had a bone dry tank. I filled my 6 GAL jerry can and poured it in. My gauge is on the tank and I marked the needle with red fingernail polish.

I did this 4 times over in the beginning and marked each 6 GAL. fill. I now know exactly how much fuel I have and how much I need to fill er up.


Just some additional food for thought pal.........

PS: remove that screen from your dip tube. It will only cause you problems.

CR

 

[Don S/V ILLusion]

Fox,

I had the same problems years ago in my 1980 C30. The vent outlet on the stern was plenty high enough but I had the same sag in the line.



CR

Height isn't important; having a loop in the line is.

Absent a loop, water can pour into the tank if the boat heels over far enough to submerge the vent. Also, rainwater can enter the vent and flow directly into the tank.

 

[jimmcgee]

I fixed this by disconnecting the line @ the tank and slid PVC pipe down the hose up to the vent fitting on the stern. I had enough slack in the hose that allowed me to attach the pipe at both ends with the hose exiting down to the tank vent.CR

Smart and simple. I like it!

This is on my todo list, you just gave me the solution.

I also like the idea of filling and marking to have a better idea of what your fuel gauge is really telling you and I'll second removing the screen.

Thanks Capt Ron

 

[jrowan]

I second that those are good ideas Cap'n Ron. I especially like the idea of marking the fuel in 6 gallon increments to know how much is left. I bought a proper remote gauge for my 1980 C 30, but have not installed it yet - (also still using the tank mounted gauge.) I have never understood why all fuel gauges are not all marked to show U how many of gallons there are specifically in the tank. I guess its because manufactures like to use generic gauges with different sized tanks, & it might actually require some work on the part of boat & car manufactures to help users. The only other rational is maybe because of expansion of fuel in hot weather is harder to measure? I have always noticed that fuel gauge needles seem to stay in the high position longer, and when they register 1/4 to 1/8 of a tank it is really only about a gallon or two left!

 

[Anonymous 121765]

Guys,

Don brought up a good post for a water-stop loop before the stern vent fitting.
I realized I left this out from my earlier post, but it's simple:

On my Catalina, if you support the PVC on the underside of the quarter berth, the stern vent vertical location will be about 3" below the PVC pipe when mounted. No matter if your location is different, as the loop you make will work.
My PVC pipe stopped a foot before the stern. I added a 45° ell at the end pointing down. I had enough hose length and fed the hose in the PVC until I made a loop. This between the end of the pvc & the stern vent fitting.

Don’t use a straight cut end as it can wear on the hose over time, and the 45°ell won’t. If the hose is too short, just add what hose you need to ensure a proper loop. This will create your water break loop for no water intrusion.
CR

 

[fox islander]

Thanks guys, excellent advice as usual. You all just added to my "to do" list.