Marine Fuel Tank Vent Problems

Condensation can be another source of water in your tank a situation made worse by ethanol added to marine fuel.

Marine fuel tank vent problems.

Is the fuel tank vent clogged. To meet the new regulations fuel tanks can no longer be built as an open fuel system. Alternatively a tank vent mounted on the topsides just forward of the transom with the opening facing downward is likely to stay dry in just about any sea condition. If your boat has diesel engines you ve heard about algae problems with diesel fuel.

Wasps spiders and other critters are well known for clogging these fittings up and that can significantly affect engine performance. Then i could fill up just fine. A boat fuel tank overflow can be caused by a clog in the vent. Shortly after i had a new fuel tank installed i discovered a problem a boat gas tank vent problem.

The fuel had pressurized in the tank in the sun no vent on that tank and when i turned the handle to steer the crack finally opened. When you open the vent on an expanded tank fuel vapors will escape. The nozzle continually shut down as if the tank were full until a gusher of gas spewed from the vent. Actually this algae is sludge a mixture of paraffin and asphalts resulting from the breakdown of the fuel remaining in the tank over a period of time as little as 60 to 90 days where it settles to the bottom of the tank.

If your boat doesn t have a portable tank but instead an integral tank with a fuel vent that s plumbed to the outside of the boat inspect that vent. Since we d had more problems as the trip had progressed and thus there was less fuel in the tank we suspected maybe there was a crack in the tank pickup. When i was a kid with an a 7 hp sears outboard engine the fuel line once split open on me and sprayed both me and the boat with gas. We did some more reading on the tempo fuel tanks that we have and found that a a crack in the pickup tube is a semi common problem and b someone had cut off the permanent fitting.

Now that portable fuel tanks must be fully sealed gas vapor is unable to vent and has nowhere to escape except to your engine through the fuel line. Taking a look on the outside of the hull and seeing if the vent is even there if it is corroded broken or upside down. The fuel tank vent is located on the outside of the boat normally relatively close to the fill port on the gunwale of the boat. If the tank is sucked in opening the vent will allow air into the tank to equalize the pressure.