Re: adjusting valves?
Since you noticed the difference after valve adjustment that's probably part of the problem. Did it miss before you adjusted the valves? Idle mixture screws may be misadjusted as well. I doubt float level would cause the problem unless it is way too high which would cause an overly rich mixture. Was compression checked before or after you adjusted the valves. If before, then you might want to check it again. If you have a lifter adjusted too tight you'll have a miss as the valve will be held partially open and compression will be low. Static valve adjustment must be done according to the service manual. If each lifter is not on the flat (low spot on the cam (valve fully closed), adjustment will not be correct. To locate the miss, use an insulated pliers and one at a time pull a plug wire. Each time you pull a wire the engine should drop off and run rougher. When you hit the cylinder(s) that have misadjusted valves, there should be little or no change since its already running bad. Even though you think you had the engine turned so the lifters you were adjusting were on the low spot on the cam, you can tell by looking at the valve ends of the rocker arms whether or not both valves are closed. If both are not in exactly the same position, those valves are not closed. Intake and exhaust valves will never both be fully open at the same time. Start with the basics. Tune up, dwell (if points system), timing, idle mixture, choke setting (if applicable), good wires, good plugs, good compression, and good valve adjustment.