HELP.........merc 150 efi revs to 3000 rpm when turning ign switch to off position

[trigby]

Does anybody know what would cause a 1997 Merc 150 efi to rev up to 3000 rpm when the key starts to the off position?Maybe bad computer? I installed new keyswitch same thing happens, have new switchboxes and trigger installed still does the same thing, runs rough at idle wont hardly stay running unless you give it throttle ,hard one to figure out...thanks for any info, Tim

 

[adeneo]

Re: HELP.........merc 150 efi revs to 3000 rpm when turning ign switch to off positio

Have not heard that one before specifically, but sounds like ignition is somehow wrong. You could check the troubleshooting charts in the Mercury service manual ?

 

[trigby]

Re: HELP.........merc 150 efi revs to 3000 rpm when turning ign switch to off positio

Ok thank you adeneo, Nobody i talk to has heard of one doing this problem ,im about to give up on it, thanks, Tim.

 

[trigby]

Re: HELP.........merc 150 efi revs to 3000 rpm when turning ign switch to off positio

Unplugged the barrell connector and the motor revved up again (scared the crap out me) so i guess i can eliminate the boat wiring,what else could cause this problem?????????

 

[trigby]

Re: HELP.........merc 150 efi revs to 3000 rpm when turning ign switch to off positio

10-4 will call ya tomorrow ,lil late now, thanks , Tim.