FDV

Hook your MEDS up to an engine (any capable engine, Merc 496 is best) and navigate through the screens for a few hours.... You will find everything you need. Not all functions work on all engines. Be careful with running tests, follow the prompts on the screen.

Update on 2014 40hp four stroke. It has the G3 ecm and can't be reflashed, unless there is a update , so travel to mercury dealer (service manager says yes bring in we'll reflash , on the phone) tech. tells me he can't reflash. But also tells me that G3 ecm doesn't go into guardian mode. Manual for 2014 with that serial # is when they were changing to single plug ecm from 2 plug ecm. So G3 ecm just reduces power at 10% intervals and doesn't , reduce power to 2500 rpm with solid alarm. Tech. said motor can run to 210 ° before ecm cuts motor back to idle. Ecm sends 5 volts to all sensors, so ect,ict,map,mat, an tps. Are resistance sensors. So as dockside said ✔ all pins and connections. Did that, now remember this is a 2014 that sat 3 years indoor storage . no corrosion , motor looks brand new. It has 62 hrs. Imo it's going to be ecm. But I can't see buying a $800 ecm to find out if that's problem. These motors are unbelivably hard to diagnose. It's getting to the point of automotive , were u just trash and buy new.
The mercury tech told me he has 4 motors in shop , after 20 yrs. he can't figure out.

That is IAT sensor not ict

If the shop has engines they cannot repair they need to move into a different line of work...

It seems that this is the type of issue you cannot repair on a forum.... To bad you are not local.

Check this out , at mercury dealer yesterday. , active fault was high input voltage to map , on his mercury software ( that's automatically updated from mercury) he wanted me to trouble shoot at there shop, he would supply tools cause fault was active. I kept trying to tell him it's active now but want be in 30 mins. So get back to shop yesterday no active faults. Can't get the six beeps. I check 5 v on p/y to map 4.98v, check y back to ecm 4.98 v. So this morning , I turn key on and 6 beeps, left motor tilted up hook computer up , active fault hi volts to map, check p/y 4.98v, check y back to ecm 4.98v, ECT and IAT are reading temp. at 32° , it's 45 ° outside. Turn key off for 10 mins. Then turn key back on no beeps. Turn computer back on , no active faults or history of faults. Battery voltage at 13.2. It's like chasing a ghost.. I'm at the point to tell customer u can buy a new ecm or buy one used that might have same problem.

It reminds me of the old B -Model peec cats (diesel) that were half and half. The biggest head ache ever made with diesel motors.. But this mercury motor is all electronic. So in my opinion it's junk. No wires moving a codes keep coming and going.

Should have said c models

Dockside, would like to person to person. Wifey's mom lives in Vineland NJ. Might be their in March.

We have boat for winter storage. You. Know. the more I thought about it. ECM sends 5 volts to all sensors . am I correct ? If so then how can ecm tell me . I have high volts at map sensor ??????????

Bumping old thread....
Gor boat out of indoor storage Thursday installed new. $800 ecm took to lake Friday, ran wot about 2 miles from ramp no beeps ( old ecm about 1 mile and 6 beeps) so said to my self it's fixed . turned around back to ramp 1 1/2 mile I get 6 beeps at wot , back it down to about 2300 rpms no more alarm. Putting to ramp and I get solid alarm ( overheat) so backed out and cut off. Waited about 10 mins. Started and putted to ramp. Took to shop hooked up cdi meds. No active faults but on freeze frames, ff1 overheat, ff2 ect overheat at 90°c. Now last Oct. when trying to diagnose 6 beeps I would get and no overheat solid beep. Called mercury tech support and talked to him ( motor tell-tale strong) he said so u don't have 6 beeps at key up ( no) did you get overheat ( yes) he said pull termostat to see if it's open or closed. I ask if thermostat is staying closed I would've got heat alarm with old ecm. He said not necessarily,
I'm like what? He said let me think for a min. then said I remember we've seen stuck close stats. or open stats. That throw 6 beeps ( map, iat or tps) now I've been chasing a fault code for map, iat or tps. I pull thermostat and its full of sand. Unbelievable , so removed back flushed and installed new thermostat , plus new impeller. Will take to lake Monday and see.