Sounds like you have a problem with your OMS pump or you have a restriction. Check the oil pickup tube in your oil tank and make sure the screen is clean. You might also want to check your fuel line and primer bulb to make sure you have no air leaks.
if the plugs are fouled, you may be running rich, check plugs for unburned fuel mixture, if that's what you find, then check for corrosion on inside of plug wires, if so replace, also check the terminals feeding the coils, I recently replaced two of mine for same reason.
Since these come from the power pack, your choice would be to replace a still good power pack (NOT ), or do like I did, the OMC dealer has replacement terminal ends and caps. I crimped and soldered mine, even though the originals were only crimped. I think they charged me $.49 each, they worked fine. Good luck !