On Monday, May 12, 2014 1:36:34 PM UTC-4, wrote:
I have this same problem with my 1997 Crownline 176, with Mercruiser 3.0LX. What did you find was the problem? Seems like possible contamination in the tank or fuel pump issue. Right now mine idles perfect, get up on plane perfect then dies quickly unless I throttle back to less than 3000 rpm. Then I can get maybe 1/4 mile before it dies out.



Thanks,

Bill

It does sound like a fuel issue. You really can't tell anything from the fuel pump vent line unless it has gas in it, then you have a ruptured fuel pump diaphram.

The suggestion to try it with the filler cap slightly loose is a good way to make sure your vent is not clogged.

Remove and drain the big spin on fuel filter. If you get a lot of water then you probably have water issues elsewhere in your fuel system. Replace the spin on filter if you have not done that in a while.

Otherwise you probably have a leak in the line between the tank and fuel pump allowing it to suck air. Or a bad fuel pump.

Fuel problems are one of the more common problems with boats. It's only gotten worse as more fuel has alcohol in it. It's not uncommon as a boat ages for the crud in the tank to increase and some of it end up in the fuel pump. If your tank sending unit goes into the top of the tank you can take it out and look down in the tank with a flashlight. Usually you can see the water/crud "under" the gas on the bottom of the tank. If you are careful you can syphon most of it out.