Fuel draining back into tank 17' Tempest 488 Mercruiser

[cajun1957a]

Every year I go through the same ritual. I can not start the boat unless I run a air line to the bow fuel tank vent and pressurize the tank while having the fuel line off of the fuel pump.. I believe there is an anti siphon valve in the tank but it is not accessible in any way. I have tried primer bulbs. They don't work. Once the boat starts it will run fine and will start easily for a couple days but when left for four or more days the fuel goes back into the tank and I have to do it all over again. Would a low pressure eclectic fuel pump work inline between the tank and fuel pump? This is an old motor but run great when fuel gets to it. What suggestions can I have from everyone? I don't want to carry a auxiliary tank as the bow tank is large and of course adds weight in the bow that assists coming up on plane.

MOD EDIT - Why should anyone email you and deprive other members of the fix when they have the same issue. Open exchange of ideas helps all of us and posting your email opens you up to spammers.

Thank you

Randy

 

[Bt Doctur]

Your fuel pump internal check valves are not working, replace the fuel pump

 

[cajun1957a]

Thankyou however a fuel pump minimally will be between $2-300. Would an electric work?

Thanks again

randy

 

[kenny nunez]

From the description of your engine I estimate it is around 35 years old and your fuel pump needs replacing like the Doc said. Another problem could be the anti siphon valve if it is one of the ones made from aluminum. I replaced many of them with the brass versions.
Every boat I ever worked on had some type of access to the tank fuel fitting. If you have to cut a hole for access there are inspection cover kits that are available.
An electric pump needs to be wired according to Coast Guard regulations so in the long run you would be better off replacing the mechanical pump.
If you are in the New Orleans area I have contacts at a dealer ship that will help you.

 

[Bt Doctur]

Nah, about 70 ish, cant get iboats site to do a search but they should sell them here

 

[Bt Doctur]

Fuel Pump Fit for Mercruiser 2.5L 3.0L 3.7L 470 86234A4 60032 18-7278

 

[cajun1957a]

Thanks for the info, however those numbers are for a pump that has the bowl facing up. Mine faces down. Ive checked out amazon, ebay, and they all face up. Any suggestions?

randy