1984 70hp Evinrude dies on acceleration

I seem to have an intermitant problem as described in the title.
When I accelerate while not towing anyone, the engine picks up just fine, but when I try to pull a skiier/wakeboard/tube, the problem really shows itself.
Sometimes it will stall all-together, sometimes I can coax it and it will eventually pick up, which is not great when you are trying to get a wakeboard out of the water.
I have noticed that after use, there is a lot of oil/fuel coming out of the air intake. When I take the air cover off, I can see fuel 'spitting' out of one of the carbs (the top one I think), but not sure if it does this when revving higher.
I have checked the reed valves, and they all apear to be well seated (removed and inspeced), the carbs too have been stripped, and nothing obvious there (although I cannot see how you adjust my carbs, they have a tube that goes into the float bowl and that's it, no needle at all). Do I need to remove the brass screw that adjusts the fuel flow?
Plugs are new and gapped accordingly, also timing and revs checked and in accordance with manual, engine run only in fresh water...any ideas?

Re: 1984 70hp Evinrude dies on acceleration

i would also check compression, here carb info. you have no carb adjustments, they are fixed jets. http://forums.iboats.com/showthread.php?t=244013

Re: 1984 70hp Evinrude dies on acceleration

Thanks Tashasdaddy, I will try a compression test and see what I get.
I should also have mentioned that the engine runs great at WOT, I get about 5600 revs, it's starts fine too and idles well, just dies under load for some reason. I have to say the problem does not appear to be as bad once warmed up.
The fact that I see fuel being spat out of the carb bothers me though, what would cause that or is it normal when at idle?
What would happen if I remove the idle orifice plug (the manual suggests that this should only be in the 50 to 60 hp engines, I have a 70, could this be the problem?) or high speed orifice plug from the carbs?