I just finished winterizeing my motor 1985 75hp seriel#6613274. I first sprayed Deep Creep into her and shut it down. While waiting for it to work it's magic I moved the throttle to wot. I noticed the upper plate was wide open while the lower was not. I can open it up an other 1/8th to 1/4 inch if I reach behind with my finger to the throttle shaft linkage. Is there an adjustment for this? I have a Seloc manuel but can not find any info on this. Also when I pulled the plugs the top two were a dark color while the lower two looked like they were brand new especially #4. Both idle/mixture screws are open 1 1/2 turns. By the bottom throttle plate not being wide open cause a leaner mixture. The motor ran perfectly all season. Am I just an old worry wart or should this be addressed. Thanks "God I love my old Mercury"