Most Indmar GM engines with the MEFI6 do not have an intake air temperature sensor, except for the LSA supercharged 6.2L engines.  High intake temperature alarms on the LSA engine is normally caused by a clogged intercooler heat exchanger, low intercooler coolant levels, or a failed intercooler pump. 

Non-supercharged GM engines should not get a SPN 105 alarm for the IAT circuit unless there is another one of the 5 volt reference sensor that failed, a wiring or voltage/ground issue, or internal ECM problem. 

Did you somehow get Propulsion plus on that boat, and maybe that is what they are cancelling?

So apparently this thing was so bad they only used it for 1.5 years.  Now mine is on the fritz, keeps powering on and off (and yes, I troubleshot it to the head unit).  So time for a replacement.  Does this appears to be a proprietary system RF made for Malibu.  In looking at replacing the &*^(ing thing, I'm wondering if I can use an RF PMX8BB as a replacement "black box," coupled iwth a PMX-CAN to interface wiht the Viper II.  Does anyone know?  If that is not an option, the 8BB will be a challenge because the head unit required for it is freaking huge.  It is 8x5, meaning I have nowhere to put it, even if I pull out the knob/wedge control/phone holder device (which I can do, as I can still use touchscreens to get function).

I'm sure there are other brands out there, any recommendations?  And if there is any way to tie the tower speakers  to teh same source as the cabin as default, that would be excellent.  I just quit using my tower speakers because it was such a PITA to make it work.

I used to do a lot of car audio, but none of that was integrated into the infotainment systems.  Last thing I did was my 2011 Axis, but I just used the old school Wetsounds 420EQ with an iPod wired to it.  On this boat, if it matters, I ordered it with the black box and tower speakers, but nothing else.  I put in full wetsounds, amps, speakers, sub.  So bear with me if I dont' follow some of what people say.

2 hours ago, CaptainMorgan said:

given your use case, if you changed to a 17" pitch prop (like the 2805 @shawndoggy mentioned, or the 2969 in my plot below), you can pickup like 3mph in cruise or keep speed same and reduce rpms by a few hundred (for either cruise or surfing).

the 2969 was too much for my old boat, but probably fine for a 23LSV with an M5/M6 at your elevation....and it happens to be listed in the classified here for half the cost of buying a new prop...just saying  

Thanks Cap'n, we appreciatecha (as they say here in East TN).  I'll definitely give that prop some thought and check it out in the classifieds.

59 minutes ago, dizzygti said:

Happens often, the pumps don't use traditional float arms anymore but rather a "sensor".   Don't worry about it unless the pump is discharging visibly and it goes longer than a few seconds.  The pumps aren't going to get the bilge "dry" and a little leftover water isn't necessarily a sign of trouble.   

what he said. I don't think of the bilge as an alarm, rather bilge pump doing what bilge pumps do. Can take on more water than you think with a chill dip.