Early 7.5 hp stalls out WOT

[x8na]

Just purchased and water tested a early '70s Mercury 7.5 outboard. Starts good, ran 3 minutes WOT, then stalled out. Started right back up, idles good, then stalls WOT. Tried to pump the gas ball in line and that keep engine running a little better. Also tried choking engine while running, a necessary given I needed to get back to launch and I was testing on a moving river. I am quessing this is a fuel line problem, but figured I would ask some of you who have great knowledge in this area. Any ideas before I go and buy all the wrong supplies and dig into this engine? Many Thanks.

 

[Chinewalker]

Re: Early 7.5 hp stalls out WOT

Hi K8NA,<br /> Could be fuel line, could be carburetor, could be fuel tank, could be fuel pump? Methodically work your way through the fuel system and eliminate what it isn't. My bet is that it's a gummed up carburetor jet... DIsassemble and clean...<br />- Scott

 

[x8na]

Re: Early 7.5 hp stalls out WOT

Thanks for the suggestions. I have sinced went through the fuel system and cleaned the carbs and changes plugs. Ran much better...but still has trouble running for long period of time. Maybe air/fuel mixture is off? What is the correct setting for this?