I have had fuel
vent issues several times on my sailboat. Here is what I have done and it seems to work without taking all the hard to reach hoses apart.
Warning this can cause fuel
spills in and around your boat. Use at your own risk, and be prepared to clean up.
This should work to clear most sailboat fuel tank
1. Get a wet/dry utility vacuum like a shopvac.
2. Take the attachment off the end of the hose so it is just the flat end of the hose.
3. Make sure the shopvac is clean and dry inside the container and the hose.
4. Put the hose on the output side of the shop vac. This is the opposite of how you normally use it. So it will blow air out of the hose instead of sucking in.
5. Turn on the shopvac and put the other end of the hose over the air vent on the outside of the hull
. The hose should fit completely over the vent and tight against the hull
6. Let it blow air into the vent for a few seconds then pull it off and let the air come out.
7. You should here the whistle from the vent if it has a whistle attached. You should just hear the air coming out if it does not have a whistle.
8. Now go below and check for fuel leaks
. Putting air pressure on the tank will show you where you have potential leaks
, loose hoses, loose caps or cracks.
9. If you finds leaks correct them.
10. If you did not hear air or the whistle you can repeat 6 thru 9.
11. If after several tries you still do not have air coming out of the vent there is one more thing you can try but it will be messy. switch the hose to the vacuum side and suck air out of the vent. This is messy because you will also suck fuel when the hose is clear. You will need fuel catch towels and probably a bucket. Try to keep the fuel from draining into the water
12. Now clean out the vacuum and go back to step 3.
Now that you have cleared you vent you should be able refuel your sailboat.
A couple of other tips for new owners. If you have the whistle in the vent I have noticed that the pitch
of the whistle rises as the tank fills. When I fill mine I slow the flow as the pitch
rises. When it is close to full I will stop and watch for foam rising in the fuel line. When I can see foam rising near the top of the fuel line I am done.
I also keep a couple of 5 gal. fuel cans full on the boat so I always have emergency
fuel. When I fill up I dump these into the tank first and then refill them with fresh fuel. This ensures that my spare fuel is as good as the fuel in the tank.
Hope this helps,