Motor stalling

[bubba]

Hey fellas. I have a 1980 aqua, with the 470 mercruiser i/o.  Every time i get out of the ramp and into the channel, i punch the throttle and the boat gets up on plane, and then all of a sudden the boat slows down like i pulled it back into neutral. Did a complete tune-up, fuelfilter. Took it out again, did same thing. Now i'm replacing the fuelpump, and overhauling the carb.(just to be on the safe side) If this doesn't do the trick, i'm clueless. Do you think it could be something electrical? I thought maybe water in fuel, but kicker motor runs like a champ.(which i used every time i broke down) Any input would be great. And the worst thing about it, is they're catching huge flatties in the a/c inlet.  :cry:  I guess there's striper season to look foward to anyway.

                                       Thanks ED

[JimCt]

Check the fuel lines.  You might be drawing air when the fuel demand is high.

[GoneFission]

Problem sounds fuel-related.  It could be a inlet valve on the carb or the float set too low, so when more fuel is needed, the engine empties the fuel bowl.  A clogged main jet or power jet will sometimes do the same thing.  A carb overhaul (including resetting the float height and cleaning all the jets) should fix the problem.  

One final idea - is the fuel tank vent open and clear?  I've seen what you describe happen with a closed or restricted fuel tank vent.  Eventually the fuel pump will pull a vacuum on the tank and quit pumping.

Hope this helps!

[RebelYell]

..

Also check your fuel tank check valve.

It does sound fuel related and "fuel starved".

 

[riverratjr]

I had a similar situation many moons ago;turned out to be the coil.

[aqua70]

sounds like your fuel pump is starting to go.You may have two of them on there. I had the same problem,
At low speed it drafts enough fuel from the tank, but at high speed when the demand is stronger the pump can not keep up.
Plus this new gas is really making things tuff.