4000 Low on Power After Repair

I'm fairly sure (?) that I've got it set to specifications, but when I hooked up the bush hog to mow down a field, it seemed like it was low on power as compared to before the repairs. I�ve fiddled with the power screw on the carb and it doesn�t seem to make much of a difference where I set it. The governor will kick in just fine under heavy load to power it through, but still it just seems like it lost some power. Any hints on what might be effecting it?

Thanks in advance,
Brad L, Medina NY

Just to let everyone know how this was finally resolved:

It seems that after putting the tractor back together after replacing the timing gears that the throttle linkage did not go back together as tight as before. When I manually 'floored' the throttle, it worked just as well as before the repair. So I guess the moral to this story is that sometimes it is the details that really matter.

And although the advance is a little bit off (timing at both idle and full RPM don�t both match spec at the same timing), the �64 has only a mechanical advance.

Lastly, good news (or not?) is that points gap and timing had very little effect on the overall performance and the full load performance is very insensitive to them.

Pull the plug wires loose one at a time while the engine's running (with insulated pliers). Chances are, you'll find that one or two cylinders are dead.

It's quite possible that you got two of the four plug wires swapped. Check the firing order vs. the rotation of the distributor.