Ted G

iTrader: (1)

You need to follow (sort of) the procedure that was outlined and get your IAC counts to 35 or so and make sure your TPS is reading correctly at idle. Also follow the instructions about blocking the air tube to check for IAC operation and that the tube is not blocked.

satisfactionII

I have a 502 MPI, would the procedure work for my engine?

Ted G

iTrader: (1)

Basically yes, same engine.

Heathsp29

you guys seem to know alot about the merc efis. i have a scarab with twin 350 mpi's and i had a problem with the starboard engine when i start it i have to jack with the throttle it tries to die and when i put it into gear or when i am running across the lake and pull the throttles back all the way the starboard engine dies. i replaced the iac valve cause the old one was frozen up and when i replaced it i started it 5 or six times and it idles up to 2000 or so. when i pulled the iac valve the shaft was compltely pulled in.im not very firmiliar with the efi stuff.when it did this on memorial wekend i just fully extended the iac and unplugged the harness from it and it acts just like it did before with the dying at idle and when i put it in gear any help would be greatly appreciated

chevalcabre

my 454 mp1 procharger fatory american offshore setup has a similar issue..

after idling dockside for 3 -4 minutes, when i leave the docks, after 3-4 minutes of no throttle cruising out of the marina,i feel a rise in rpm, i put it in neutral and i get a 2000 rpm that wont come down no matter what !

any ideas ?

chris2k2

Needed an IAC for my 502 MPI and no local Merc dealers had one in stock . Matched it up at the local auto parts store with MASTER PRO PART #21755 or 2- IAC2. Works perfect and cost was $26 as opposed to Merc $90