surging idle
 

I had my 98 Baja boss 272 with 502 mag mpi at loto this weekend and had a bit of a problem.. Sat am, we went to go on plane and I could hear and feel the engine missing.. I back it off, shut down, and restarted.. this time when I went to take off, there was a lot of smoke out of pipes so shut it down instantly. raised engine hatch and there was water in the bilge up to the water pump and the belt had thrown water everywhere... Turned the bilge pump on and checked oil.. it was a little low but looked good.. we idled back to dock to top oil off and went back out... When I went on plane everything seemed ok.. we stopped to get some more oil and continued to the shootout.. as I took the boat out of gear to park, the idle shot up to between 1000 - 1200 rpm and sat.. I shut the boat down and we tied up for the day.. a few hours later, we started it up and it started a surge after a couple of minutes warming up.. it surged between 600 and 800.. I put it in gear at low point of surge and we headed out.. from here on, it was intermittent but still seemed to happen, when it did, after warming up.. I'm leaning towards the possibility that some moisture got in the intake from the belt flinging water around.. Any ideas where I start my trouble shooting ,,,

first thing I would want to know is how did that much water get there. then I would figure the water was there the night before and something got moisture in it let it dry with the hatch up and see if it goes away.

Did you determine where all of the water came from?

I think its just a rubber exhaust coupler... I just had this engine rebuilt and installed 40 hours ago... I noticed it dripping down by the boot after the silent choice down to the prop...

Water got sprayed up into the intake area and boogered up the IAC. Had a similar issue happen when I forgot to put the exhaust drain plugs back in. Oooops.....

where is the IAC.. I read some other blogs talking about this and haven't approached that yet.. Is it expensive??

actually, I found it.. any problems with using a borg warner???

IAC is in the throttle body area. Not sure about the price. I just let mine dry out and it still works to this day.

mine is not retracting with the spring pressure.. would that mean its shot??? and can I use a borg warner brand??

You mean the solenoid is not moving the pintle? Again, not sure about the Borg Warner brand. If it fits and is a 5V reference my guess is it would work.