Hello Ben,
Before changing the settings in the warm-up device, find out what the engine needs to raise the cold idle. During the warm-up period disconnect the linkage rod from the injection pump. With the linkages still disconnected, move the linkage going to the intake open slightly. If the rpms increase, then the engine needs more air, if it faulters then it needs more fuel. Next move the linkage open, going to the injection pump slightly, if the engine rpms increase more fuel is needed. If the engine faulters more air is needed.
Need for adjustment at the warm-up device is unusual since this is a factory setting. Realize that shortening the length of the plunger in the warm-up device will allow the air valve to stay open longer and open wider during warm-up, however it will also increase the quantity of fuel injected during and AFTER warm up cycle.
Before changing this do the test as described above and relay the information if you like. Let us know what you find.
Joe Alexander
Blacklick, Ohio