Mercury XR4 1990 model

I was getting my XR4 ready for a compression test. Hooked up the water, turned the engine over and it ran good. I put it in forward and suddenly it took off like a bat out of hell (didnt even push throttle over 25%). I put it back in nuetral and still running up around 2000rpms. Turned it off, then back on and still ran around 1800rpms. I dont know what happened really. Checked stator, trigger, power packs, even unpluged the control idle module to see if it failed and still high rpm. Their all still good, I cant seem to figure out what happens. I know if I start the engine and I pull the trigger plate towards carburators the engine lower in rpms. Can it jump time, or is somethong else causing the engine to function improperly? Please help