High RPMs in Neutral After Operation

[Don't Blink]

I have twin 2003 Mercury 135 HP OPTIs, with approximately 1200 hours on each engine. Recently the port engine will intermittently and briefly rev high and drop back to normal when I go into neutral after slow forward operation. Sometimes an alarm will sound briefly. I have not done anything to resolve this problem, yet. Any insight into this issue would be greatly appreciated. Thanks, Don't Blink.

 

[GregCO]

S

I have twin 2003 Mercury 135 HP OPTIs, with approximately 1200 hours on each engine. Recently the port engine will intermittently and briefly rev high and drop back to normal when I go into neutral after slow forward operation. Sometimes an alarm will sound briefly. I have not done anything to resolve this problem, yet. Any insight into this issue would be greatly appreciated. Thanks, Don't Blink.

Since you have twins swap out the PCM’s from side to side and see if the problem goes to the other engine. If it does then replace the PCM.

 

[flyingscott]

Hold up before you start changing PCMs. Pretty sure you have a TPS sensor. And make sure the throttlebodies are closing,

 

[GregCO]

Hold up before you start changing PCMs. Pretty sure you have a TPS sensor. And make sure the throttlebodies are closing,

Good point. They could be hanging up a little.

 

[Don't Blink]

thanks for the reply

 

[Don't Blink]

Hold up before you start changing PCMs. Pretty sure you have a TPS sensor. And make sure the throttlebodies are closing,

Thank you I'll try it

 

[flyingscott]

Take it to a dealer and pay for the scan,

 

[Don't Blink]

Thanks for all the responses!