Re: 1981 Evinrude 70 HP E70ELCIH Skipping motor
I'm with daviet, my guess is that your problem is due to either compression, spark or fuel.
Spark test: get an inline spark tester (about $6 at autozone), set the gap to 7/16", clip it to the engine block, attach the plug leads (one at a time) and look for spark while cranking. If it won't jump a half-inch gap in the open air without a spark plug, then it won't fire in the heat & pressure of the combustion chamber.
A light coating of oil on the plugs after idling is good. Are they champion QL77JC4?
Sorry, we won't be able to tell if your fuel tank pickup is clogged with debris -- that's pretty much a visual inspection, so we'll need you to check on that and get back to us. (

sorry, couldn't resist)
by "cleaned carbs," do you mean "disassembled, soaked overnight in carb cleaner, reassembled with new carb kits?"
Just a heads up...when you detect a hi-speed misfire (or a low speed misfire either, for that matter), stop using the motor until it's diagnosed and fixed -- if it turns out a cylinder is starved for fuel, that cylinder is also not getting lubrication.