Unusual Symptom has me baffled.

[joxster]

The last time I had a mechanic work on my engine he spent three days looking for a problem that turned out to be very simple. The part was $12.00 and it cost me $900 for him to find out I needed it. So I am on a quest to pin point this problem first. I have searched and searched. Perhaps there are some people who have had this problem before.

The 1999 Johnson 150 (J150PLEES) engine will not run for more than a few minutes on a plane. I noticed the primer bulb was flat and made a guess that the line was clogged. I removed the bulb and blew air back through the line towards the tank. That worked for a few minutes. The problem repeated. Blew the air again. Fine for a few minutes. Then the engine died. The bulb was no longer flat. I pumped it and fuel made it to the fuel pump but would not start. It seemed as though the fuel was not making it to the carbs. After hours of trying trusty Sea Tow brought us home. I let it sit for a couple days and it started right up. I took it for a test run and it did the same thing all over again.

Any thoughts would be greatly appreciated

[boomer2]

Anti siphon valve maybe. Put a portable six gallon tank and hose in the boat, hook it up and see how she does with that.

[boomer2]

Primer bulb maybe after blowing air backwards thru it... Championman will be along directly..

[joxster]

Thanks for the idea. I removed the bulb and blew back through the line only though. The part that confuses me is that fuel seems to make it to the pump. I loosened a screw and it sprayed out with a lot of force.

[dearjhn]

X2 Anti siphon valve, I had the same problem on 200gt, this is what it was.

[boomer2]

You can get fuel to the pump but still have a problem because the volume needed isn't there. For the correct volume to get there the pick up tube, primer bulb, anti siphon valve and fuel filter (along with any inlet/outlet screens in carbs ) need to be clean and working correctly.

[joxster]

Sounds unanimous. I am headed out to replace that now and see how it goes. Thanks for the valuable input!

[Bassmeister]

Either knock out the ball in the anti syphon valves, or replace with appropiate sized brass ells..

[evinrudeman]

Sounds like it's time for the clear line and vaccum gauge test. No more than 4in of vaccum between engine and fuel tank,and NO bubbles. Low vaccum and bubbles indicates an air leak. Portable 6 gal tank is a good test. If all is @ spec,its time for a new fuel/oil pump.

[joxster]

Thank you all for the advice. It was not the problem but led me in the right direction. For anyone that may come across this in the future, my trouble turned out to be the fuel tank vent. The brass fitting had a check valve in it and it became stuck. So with no air in the tank the fuel pump could not get fuel. Which in hind sight explains why it only happened after I headed out from my dock and got up on a plane.