Fast Idle, No Throttle Reponse

[Water Sports]

First of all Happy Summer!!   Now the problem--the engine starts  and runs smooth--the rpm is at 1800 and will not idle down, and the throttle is unresponsive.  The red light stays on all time.   I've read several past threads on this subject--believe its called 'limp mode'.
I have access to other engines,  so I started by replacing the entire throttle body,  same problem. 
Am I missing something? Bad electric connection?  What sensor controls the idle and throttle?  Do I need a new computer,  scan tool?
Ran perfect last year,  changed gas filter and fired it up and got this situation.
As always thanks for the info.   Doug

[CherokeeEpic22]

my boat did this but i had good throttle response, but my high idle was caused by a bad fuse in the fuse box located on the top back of engine. i rented the scan tool from capt rick to find this out.

[Water Sports]

Thanks for the suggestion, but the fuses are good.  Still searching.

[ktdust]

How do the spark plugs look?

[Water Sports]

They look good, runs smooth at 1800rpms-the only rpms achievable,  but I'll change them out tomorrow.  Thanks.

[sailtl]

Reset the computer after you change the plugs.  How? Shut off the Perko switch or disconnect the battery for at least 30 sec.

[Water Sports]

New plugs, reset computer---still same situation.  Needed to change them any way.  Thanks again-testing further.

[Water Sports]

Finally narrowed down the problem--throttle body --what part, don't know.  I made a mistake, I 'assumed' the extra throttle body worked, it was malfunctioning also.  Reading the threads over and the service manual everything pointed to the parts of the throttle body.   Tested the ohms of all three parts and they read normal.  Read in the service manual ( SF-31) that the throttle control motor would hum with the ignition on and would react when the accelerator pedal position lever was moved, this one shut off when the lever was moved.  Tested a running boat-no more assuming-and the throttle motor would react, took the throttle body off and put it on the broken boat and it runs perfectly.  Now I have to figure out which part of the throttle body to fix.  Any suggestions?  Thanks

[wakejunky]

usually and i mean usually its the throttle lever sensor ( the one the cable attaches to) i would swap the sensor over and check given you have a good throttle body

[Water Sports]

FINALLY found the problem, after switching out the two sensors, the throttle controll motor would still cut out when the throttle was moved.  Dismantled the motor and found a bad bearing and corrosion on the coil and magnet.  Replaced the bearing and removed the corrosion.  THANKS for your help.  WakeJunkey looking forward to your scanning tool.  Love these engines, lot to learn.