Boater I can have you talk to one of our techs tomorrow. My cell number is on our website. Dustin Whipple has his hands full. If we can help. We will

Brett

Performance Boat Center

Very nice of you!

Thanks Brett. I may have to do that. I am trying to get my hands on a wiring diagram for motor. Called Merc HP today. Tech said he had not heard of that problem before and did not have a wiring diagram there. Not much help. I just picked up a service manual tonight and will see If there is a diagram in it. If I cannot make any progress on it I will give you a call next week after the holiday. Again thanks for the offer I know you guys are very busy.

Check the resistance across the leads of your IAC, it is probably shorted which will cause the fuse to keep blowing. The IAC and boost control valve are on the same fuse so this could be the source of your low boost issue. Be careful swapping parts because a failed IAC (very common on these engines) can damage the ECU so check both IACs if you've been swapping parts back and forth. I recommend installing a 1 AMP fuse inline with the hot lead of your IAC to prevent damage to the ECU. Dustin is the best person to talk to and has been really helpful and responsive on this issue with me in the past but as we all know this is bad timing. R.I.P. Mike Fiore.

If you find that your ECU was damaged by the failed IAC then your only options are to have Dustin repair it or purchase a new one from Mercury$.

Brett, I stayed at Red Head Yacht Club for the Shootout and attended your party on Thursday night. You guys are awesome and your facility is fantastic!

GF?

Thanks for the info GF? I will compare the ohms reading between the two IAC . That is the info I was trying to get out of Merc to determine what else was in the circuit. The IAC was the only thing I did not swap out. Dustin had done an IAC repair on the other motor ECU in 2010 he wrote it on the back of the Starboard motor ECU. You may have solved my problem. Man I really appreciate you pointing that out. Starboard motor is still running as normal so hopefully I have not damaged anything. I will check it out in the morning. Thank you!

Where exactly is that fuse ??for me to check - i have the same problem on a 700sci .tks

Rear of starboard side valve cover on top, attached to black bracket. 2 black plastic fuse holders side by side . Says fuse on top of cover. Its the one closest to the header. Has four fuses in it. It is the first yellow 20 amp facing rear of motor on right of fuse block. Has red/green stripe wire and red with small blue stripe wire connected to fuse female sockets.
Fuse pack C27 - Position CD- powers IAC, boost by-pass, Driver power

thank you sir !

Makes perfect sense. If that fuse is taking out the boost control AND the IAC then you're not going to get the idle enrichment/high idle as the IAC opening is what's needed to get the motor idled up

Thanks everyone for your help and comments. Just compared IAC resistance readings. I have a bad IAC. Good IAC read twelve on digital ohm meter with a tone. Bad IAC read 290 which is high resistance and will cause a higher amp draw and blow fuse. I have one on order will be here tomorrow. I will let you know what happens after install. Hopefully I did not damage anything else and it fixes problem. This problem did not trip a code as stated that it would in other thread about IAC ECU repair. Again thank you all and Brett your offer was very over the top and appreciated.