collapsed fuel primer bulb

Discussion in 'Outboard Maintenance' started by --AL--, May 22, 2013.

  1. --AL--

    --AL-- I Love!

    I was running Biscayne bay in some chop and the my outboard started sputtering and died. There was no alarm, temps were fine, nothing fouled the prop or was blocking the water intakes and I had plenty of gas. In restarting the engine, I noticed that when I squeezed the primer bulb it stayed compressed. I kept squeezing and messing with it and noticed the engine would stay on when I did that. Eventually the bulb reflated and all was well. This happened again about 20 mins later and was 'fixed' the same way. Well, we ran for several hours after that and it never happened again.
    Also, waters were rough that day and when running rough areas I noticed a slight smell of fresh fuel. I figure its sloshing gas leaking through a vent? Whats going on here? Any troubleshooting procedures? Thanks.

    boat: native suv
    engine: 40hp Honda
    fuel tank: 12 gal aluminum
    fuel: only rec gas no ethanol.
  2. Dillusion

    Dillusion devilray snob

    When the outboard is sucking fuel out of the tank, it creates a vacuum. Sounds like something was blocking air from entering the vacuum that's created. Maybe the rough waves got water and debris into your fuel tank vent and the vacuum sucked all of the air out collapsing the bulb. Once you cut the engine the vacuum was released and whatever was in the vent or vent lines was able to relax or be released.

    Might be a stupid answer but it's all I can think of lol

  3. HaMm3r

    HaMm3r Well-Known Member

    You have a vent on that aluminum tank that could have been closed or blocked? If not, I'd replace the primer bulb. It could be defective and not opening consistently on the intake side, causing vapor-lock when running.

    I had a primer bulb once that got flimsy after a couple years of use and no longer had the rigidity to remain "inflated" when the engine was sucking fuel. It would randomly collapse and had to be replaced.
  4. Creek Runner

    Creek Runner Well-Known Member

    1) Clogged vent, either you have a vented cap or an external vent.

    2) Primer bulb is bad

    3) Anti siphon valve in the pick up tube is bad.

    Any of the 3 can be the culprit, start by making sure you vent is clear, R&R primer bulb, and then R&R anti-siphon
  5. cutrunner

    cutrunner Cert. Yamaha technician

    Glad your on top of it.
    By the time I see these threads the op would have given up
  6. --AL--

    --AL-- I Love!

    Thanks for the replies. I'm hoping the vent is bad because i'd hate for there to be crap in the tank. So here's a pic of the top condition of the tank:
    Looks pretty solid but then I see this:
    That yellow gunk, lower right hand side looks and smells like gas. When I opened the compartment initially I smelled gas. How would gas leak from there if it has an external vent? There is no wet gas, however, and the fuel level is exactly the same as last weekend so I don't think its tank welds leaking. Maybe the tank fill port fitting isn't 100% leak proof? Here's a pic of the vent.
    Busted vent theory seems the most likely case. Primer bulb is brand new and looks fine and I'm crossing my fingers it's not the anti-siphon valve as that will ruin a few weekends (Or vent sucking up a bunch of seawater in the chop  :(). Gonna have to set up an experiment to test this bad boy. I was thinking filling up a trash can with water, stick engine inside and run, cup hand over vent? Any suggestions here are appreciated. This only happened twice by the way (engine cutting off) it worked fine for hours after that. It just happened while escaping a storm in choppy water kinda far from home.
    Anyway, I sent Ankona an email the other day about this but probably gonna have to call them up.