I have a 1952 case SC with a Fairbanks Morse Magneto been having a problem with the tractor missing under load the more gas I give it the worse it gets seems to miss sometimes when the angle of the tractor changes like on hills. But mostly under load or just holding the brake. I can usually stop the miss by decreasing the gas. Id appreciate any help plugs are ok. spark is a little weak but has always been like that. I can only say it has compression but don't know how much.. I did check the timing yesterday everything to specs. I sprayed around the manifold to check for leaks nothing. Sure could use some help on this one guys. I'm going to check the valve gaps today I set it last year I did check for a broken valve spring that was the problem last year. I did screw up the governor settings that were kicking under load before I fixed it! I decided to straighten the linkage out from the carb to governor lever. I tried to reset it to specs but no luck. Sure could use some help on this thing guys. Any think you can think of may help Thanks in advance.