Fuel Vent Question

[xavier]

I have a 1984 170 with a new 2017 90 Suzuki. I recently was filling my gas tank using 5 gallon tanks I had filled up at gas station. The boat was attached to my truck. The fuel usually flows out of the vent when full. This time the gas came all the way up the fill hole,but did not flow out of vent. After driving with the boat on trailer I noticed the fuel draining out of vent down side of hull. The gas gauge read it was 3/4 full but not sure if I can rely on the accuracy of gas gauge all the time. Anybody had this happen or can weigh in on what I should do if anything?
Thanks!

[RickK]

Check your vent for mud dauber nests - pretty common.

[xavier]

Ok thanks will do.

[boatnamesue]

When filling by gas can versus pump, using the latter flows fuel into tank with significantly more force causing the pressure building in the tank to release via vent.  Filling by can is passive thus much less pressure needing release. 

Feul gauge reading wrong level is separate from above.  Check sender continuity.  If good, check sender float isn't sticking.  If not, replace. 

[Blue Agave]

How old is the vent?  Is it original? If so, go ahead and replace the vent. 

[xavier]

Thanks, for the advice. The vent is original. I will check into the the other items and fill it up at the gas station and see if that makes a difference. I also think the gauge wire needs to be replaced. When I open port and move the wire that attaches to fuel tank the gage jumps around. 

[xavier]

I was told it could be the fuel fill hose holding gas not sure how that happens?