01 Optimax 200hp rough idle in gear

[SLambeth]

My 01 Optimax 200 will idle ok in neutral, but it will die when put in gear before it gets warm to normal temp. The serial number is OT371603.
I have replaced the plugs recently and it runs better, but has the same issue till it warms up. This is common after fishing for a while when the engine cools back down also.

Let me clarify- the motor idles rough before it gets warmed up to temp- 115F or so. If I try to shift into gear before operating temp, it typically will die. Any suggestions???

Thanks-Sean.