How do you reduce the fuel on an old 40 series H Motor?

Dave.
Its not difficult, but you require the right tool.

On the back end of the injection pump there is a round locknut with a screw thread protruding out with a hex on the end. The locknut has 3 holes in the face and this is where the special tool is used to undo the nut then you can turn the centre screw out to reduce.

There is also a stud on the front timing case where you can inspect the static timing mark (from recollection should be 11* btdc.)

I made up a tool years ago when I had a 2h (same pump). to make the very adjustment you require.

You may be able to get one from Toyota.
Hope this of some help.
mike

Hey Tour boy,
Before you go adjusting your fuel check the EDIC motor position. There is an eletric motor bolted under the inlet manifold with a rod going to a lever on the injector pump. When running the little lever should be in it's central position, on start pulled back towards the EDIC motor and off, pushed forward. It's not at all uncommon for the motors to wear and stick in the 'start' position which richens the fuel mixture and thus blows black smoke.
If the EDIC is working correctly the you can adjust the fuel via the afore mentioned method, although a good pair of vice grips will work well enough on the lock nut. Done it plenty of times.
I'd be questioning why you would need to adjust it though. if you're injectors are in poor condition you will blow black smoke through poor combustion, like wise with a worn injector pump. Timing shouldn't ever need adjusting unless something is worn or altered.
Good luck,

Dan

Is it running rough? if it is the diaphragm at the governor end has a hole in it and that will give you full fuel all the time . Not a fun job, only ever seen three vehicles with that problem in god knows how many years.