Pontoon Boat & Deck Boat Forum

2008 21' ST PB, NV Strakes, 90HP Merc

I have some question regarding fuel tank venting on my boat. Back when I bought the boat in 2012, it had stock fuel tank venting which consisted of what appears to be a vented gas gap. The tank is normally surround by water. But the cap sits upon a tall neck out of the water and can certainly can become wet from water splashing, but it does not appear to ever become submerged.

So when I took the boat into the dealer for a fuel starvation problem, in addition to replace the VST float switch, they made a venting mod too. They drilled and threaded in a 3/8"h metal nipple into the metal plate atop the tank, and hooked a long rubber hose to it, and ran it up my taowbar as to be out of the water. It then looped over as to not catch water. So now the tank is vented to atmosphere with NO filtering mechanism in the hose, to prevent moisture from entering the tank.

I am now getting ready to install the third VST float switch on the Merc and I am wondering if this could be related to the mod mentioned. I would hope that they did this at the direction of ST, if it were really needed. Maybe someone can confirm? So last weekend, I removed the hole and plugged the nipple and returned to the stock venting through the air restricted fuel cap, mainly for the Hell of it.

So what do you guys think? Should I stick with the stock gas cap venting? Or re-install the modded vent that the dealer did?


Thanks

the tank should have a molded in barbed vent fitting that accepts a hose which gets clamped and runs (or ran) up to your original vented fuel fill system. sometimes the vented fuel fills don't work so well, and to eliminate it, you would install a separate fuel tank vent and either cap off the vent tube on your fill assembly, or change that out also to just a fuel fill without the vent tube. attached pics; the common vented fuel fill assembly; and just a separate fuel tank vent. it sounds like the dealer did some kind of rookie engineered vent, that may work based on design, but looks like crap, and the first time mud dobbers find that tube, there goes your fuel venting.

Pretty confident, I have nothing factory that looks like that.

Might be wrong, but I think the factory venting is that vented gas cap, and nothing else. I really need to look closer, and grab a few picks of the top of the tank, next trip to the lake.

wrd1972 wrote: ↑

Tue Aug 14, 2018 9:31 am

................ They drilled and threaded in a 3/8"h metal nipple into the metal plate atop the tank, and hooked a long rubber hose to it, and ran it up my taowbar as to be out of the water. It then looped over as to not catch water. So now the tank is vented to atmosphere with NO filtering mechanism in the hose, to prevent moisture from entering the tank.....

Maybe what I'm picturing from your description is different from what they did, but that really sounds like some sort of halfa$$ redneck modification! I can't imagine how crappy that looks. It sure doesn't sound like anything a true professional would do!

Sounds like they are barking up the wrong tree?

Agree with the above. Might need to call Suntracker and simply inquire.

Let me ask you guys this. Is it "plausable", that the only factory venting of the tank in this boat, was the vented gas cap? And NOT any additional factory installed, vent hose? I am thinking this is how it was then the dealer simply added in the vent hose mod.

I wouldn't call it redneck, they actually drilled and tapped the aluminum sending unit instead of trying same on the thin plastic tank.
A lot of boats with small/portable size tanks do not have enough venting when filling tank OR they use the filler neck as a vent.
You get a lot of burping while filling or you can not fill tank completely.
I dont know why they added a vent tho, unless tank was sealed and it actually had a sealed cap, not breathable one.
That could cause an issue with vacuum gorming in tank starving fuel.
Do you run ethanol gas?