70HP Drops a cylinder

Have a 93 Johnson 70 HP with a 2000 power head. Runs fine all day at 4,000 RPM and below. At full throttle (5K RPM) it will run a little while and suddenly drop one cylinder. I can "limp along" at 2,300 RPM OK, but try to exceed that and the cylinder drops out again. Turn it off and park for 15 minutes and restart it, and it seems fine until I do the full throttle thing again. Did compression check and all cylinders were high and right together on the reading.

I'm thinking either a coil or powerpack. Hate to just throw $$$ at it tho.

Suggestions?????

Thanks

Tom

Do a cyl drop test on it when the prob happens. This means pulling one plug wire off at a time with an insulated pliers to see which cyl is acting up. Then go from there. Fuel or ignition ?

Use a timing light ( one cylinder at a time ) to determine where the problem is.

If you use a timing lite ( if you have one ) turn the timing lite around and look into it. When the prob occurs you will see black spots. Cyl not firing.