Marine Fuel Tank Vent Problems

A boat fuel tank overflow can be caused by a clog in the vent.

Marine fuel tank vent problems.

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 the tank is sucked in opening the vent will allow air into the tank to equalize the pressure. Wasps spiders and other critters are well known for clogging these fittings up and that can significantly affect engine performance. 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.

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. 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. Then i could fill up just fine. Is the fuel tank vent clogged.

For safety reasons opening the vent should be done off the boat on a level surface with good air circulation in the area and no ignition source present even cell phones. 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. 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. To meet the new regulations fuel tanks can no longer be built as an open fuel system.

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. Condensation can be another source of water in your tank a situation made worse by ethanol added to marine fuel. The nozzle continually shut down as if the tank were full until a gusher of gas spewed from the vent. If your boat has diesel engines you ve heard about algae problems with diesel fuel.

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. 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 you open the vent on an expanded tank fuel vapors will escape. 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.