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  Topic Review (Newest First)
10-16-2013 06:32 PM
Re: GS 39 Fuel Tank Vent Line

Just returned from six weeks of cruising in the San Juans. I added fuel twice--about 30-40 gals each time. The first time, the vent seemed to work normally--no backup in the fueling pipe and it took less than ten minutes. I filled the 80-gallon tank to about the 70 gallon level so I don't think any fuel was forced into the vent line. After a month of cruising, I refueled. This time it took almost a half-hour, since the fill pipe repeatedly backed up. No fuel exited the vent line into the overflow bottle. My guess is that sailing and rolling with a fairly full tank, forced fuel up into the vent line and it settled in the lower part of the line, blocking the venting. I know the line needs to run continually uphill to the transom vent fitting but it seems I would have to tear up the cabin sole to get access to the area where the original copper line was installed. Not an option...

Any ideas how I can "purge" the vent hose before refueling?
07-24-2013 06:03 PM
Re: GS 39 Fuel Tank Vent Line

M? (I'm guessing, from your email address),

You can probably guess that we don't use the boat that much when I tell you that I haven't refueled since my last post about fuel probably sitting in the new vent line. This is how I ran the hose that I used to take the place of the copper tubing: I drilled a 3/4 in. hole thru the sole, just inbd. of the stbd. settee (under the fwd. drawer) and another at the aft end of the settee (under the aft drawer). The hose goes from the transom fitting (after adding a hose barb) fwd, then inbd. thru a gap below the wall (under the instrument panel area), then along the hull and alongside the engine into the bilge area. From there it goes up thru the aft hole in the sole to the fwd. and then to the tank. I don't remember the length so you would have to measure (and over-estimate...). To lead the hose, though, I had to work from front to back, mainly because of the difficulty of getting the hose through the aftermost hole--can't reach it from below so I had to run it down and then grab it from below. Helps to have help...

You can see why fuel forced into the vent won't drain back into the tank-- I'm trying to think of a way to purge the vent line before fueling. Any ideas?

Cam Foster
07-23-2013 05:18 PM
Re: GS 39 Fuel Tank Vent Line


I have a similar problem. I also get diesel in the bilge if I top off the tank. I'd appreciate knowing of your struggles to access and replace.
06-21-2012 01:39 PM
Re: GS 39 Fuel Tank Vent Line

I recently added fuel and initially had the old problem of the fuel backing up in the fill pipe. Then I noticed that there was a little fuel squirting out of the vent line at the transom (into a "capture-cup"). After that stopped, I didn't get any backup and could fuel at a normal rate. That gave me the clue that there had probably been some fuel sitting in the vent line. I had not been able to install the line in a continuous uphill run from the tank to the transom vent, allowing any fuel that gets in the line to run back into the tank.

02-16-2012 04:36 PM
camndon Thanks--

When I refueled back in Sept. I was very cautious but it seemed OK. I'll give it a better check this summer.

02-15-2012 07:59 PM
Originally Posted by camndon View Post
That post was one I put on about 18 months ago. I finally got around to changing the vent line--installing a fuel-quality hose. Let me know if anyone wants the (ugly) details...

Sorry you didn't get more help earlier... but these boats are not particularly common, I suppose (Though we know of another one in Pt Roberts)..... presuming that the switch-out cleared up your problem?
02-15-2012 07:49 PM
camndon That post was one I put on about 18 months ago. I finally got around to changing the vent line--installing a fuel-quality hose. Let me know if anyone wants the (ugly) details...
10-16-2010 03:54 PM
GS 39 Fuel Tank Vent Line

I've been having trouble for a long time in fueling the boat. The tank fill hose backs up unless I go exceedingly slow (ten minutes to put in 20 gallons). It's clear to me that the vent line is plugged--it doesn't appear to be "crimped" anywhere that I can see it. I've cleared it at the outlet end. Now I'm thinking of replacing the copper tubing with fuel line hose. Has anyone out there dealt with this? If so, how did you manage to run a new line since it is so hard to access the space under the main cabin sole?



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