Re: '77 4hp "dead spot"?
On the top side of the carb and under the flywheel is the throttle cam. Twist the throttle handle toward "fast" and you'll see it move from right to left (low speed to high speed). There is a small roller that follows that cam. The roller is attached to the carb linkage. On the right (slow speed) side of the cam, are two little "hash" marks, (could even be only one hash mark). As you turn the throttle handle toward "fast", watch the roller, as it reaches those hash marks, the throttle plate(inside the carb) should just barely begin to open. You'll need to watch the end of the throttle plate shaft on the left side of the carb to see when it barely starts to move. I made a "special tool" for this out of an alligator clip and a short piece of wire. Attach the clip to the end of the shaft and this will magnify the throttle plates movement and be easier to see. If the throttle plate doesn't move at the same time the roller reaches those hash marks, you'll need to adjust the linkage so it does. Don't "bend" anything to make it work. Just position the roller on the marks and hold it there while you make the adjustments. I can't explain to you how your particular linkage is arranged so, you'll need to look at that yourself. At least now, you have the basic principal of a "link and synch" adjustment. This is critical for good performance and once you understand the procedure you'll see how easy it really is. Keep us posted.
I hate to ask , but could you try and explain that one?