OK Gents,
Another 496 issue.

I scanned a twin 496HO (2002) install last night attempting to find some kind of error codes for the following issue(s).

Client states that after running for a while and shutting down, the port motor won’t start. Cranks but does not fire. After idling around for a while (~20 minutes) on the starboard motor it then restarts.

I hook up the Diacom and read all the general active errors associated with Smartcraft…
Pitot Ckt Lo
Fuel Lvl Ckt Hi
Ster Pos Ckt Hi
Trin Ckt Lo
Fuel Lvl2 Ckt H

The history errors are the same with some sporadic errors (overspeed, sea pump, etc…) but none in recent hours.

Nothing here………

So I fire the engine up and the first thing it does is peg the IAC at 99.99% and is hissing like crazy. Very rich I might add. I let it warm up and it starts surging on and off the IAC. The TPS reads .52V.
If I increase the throttle/TPS to .67 volts it smoothes out a quits surging.

Sooooo…I’m wondering if I need to increase the throttle screw and reset the TPS back to .5V. Sounds easy but………
1. Why would this have moved?
2. Could the blades be closed and it can’t get enough air to start consistently by utilizing the IAC only?
3. Why would it start after cooling a bit? Possibly due to cold IAC start setting is opened more?

Sounds like it may be an easy fix after writing this…
Thoughts?
Thanks,
Dave

Normal IAC operation on a 496HO will be to go to 99.99% at startup and then drop down and vari rapidly between 20% to 30% after 30 seconds or so.

Before trying to adjust the throttle plates, have you tried to clean the plate and throttle body?

Dave