2016 250 pro xs first start in the cold

[Jtreed99]

My 2007 250 pro xs has always done this. Only on the first start and only when cool. A little worse when trimming and starting simultaneously. Always get the extra beep then. Every subsequent start just breathe on the key and it’s instantly running even with trim and livewell pumps going. I’ve cleaned terminals and wired around switches until I’m blue in the face. I just accept that it’s gonna do it and move on since the issue only exists for a single start each day.

[EuropeanAM]

Some of the PCM calibrations actually had a "nuisance glitch" that caused this, as well as a First-Cold-Start "Neutral Overspeed" fault. Usually only happened when temps were below 60F.

Didn't require any action for that symptom (ie: leave it be).

Now if a battery, cable or connection was bad... it probably wouldn't start under those conditions.

[Jtreed99]

Thanks Don! Do you a range of serial numbers that might be affected? Or a rough time period of PCMs? Is it worth it at all to have anything flashed or replaced if there are no other issues?

edit: forgive me if this is hijacking as that is not my intention just a general question about which ones are most likely to have that version of PCM calibration.

[wisranger]

Don’t worry about hijacking! All of this stuff is interesting to me and I’m sure many others. I had a 2009 225 pro xs and that engine never sounded an alarm on a cold start under 40*. Just trying to figure out a way to stop my 250 from doing it.

[EuropeanAM]

Thanks Don! Do you a range of serial numbers that might be affected? Or a rough time period of PCMs? Is it worth it at all to have anything flashed or replaced if there are no other issues?

edit: forgive me if this is hijacking as that is not my intention just a general question about which ones are most likely to have that version of PCM calibration.

Seemed to creep in around July 2006, have seen it even in the latest calibration (though the Neutral Overspeed fault is now gone).

I would not recommend altering the calibrations, the ones that tended to log the overspeed faults were actually a very stable-running (and strong performing) one.

[lpugh]

Bypass that switch- and make sure you have clamp-style terminals on the battery (use the threaded lug on the Clamp-Style terminals for the ENGINE connections).

Built-in screw terminals and Battery Switches are the two most common areas we see problems with current-carrying capacity.

I have seen many instances of batteries failing a test when tested from the screw terminals, but pass when connected to the lead post, something to keep in mind. The worst offender in this regard being the Optimax batteries

[afbr]

Mine does the same thing. I have even replaced the battery this spring. Always does it on the first crank of the day no matter the tempature.

[tomloans]

Well I also had the same thing until I cleaned my injectors and replaced the o-rings and sleaves. The motor no longer coughs and smokes in the morning at first crank. I have more power and responsiveness. The hole shot has dramatically improved. One of the best things I did to this engine in regards to noticeable results.

[afbr]

I have just noticed that I have about 5' of extra battery cable length. Could that cause this issue?

[Savage]

I have just noticed that I have about 5' of extra battery cable length. Could that cause this issue?

Not if the cables are in good shape with no internal corrosion.

[kbad]

My 2007 250 pro has done the same thing since new,with 4 different batteries.

[EuropeanAM]

I have just noticed that I have about 5' of extra battery cable length. Could that cause this issue?

12' cable is standard on these engines.

[Toby]

Don, when you say bypass the the on/off/jump switch, should you leave the the power wire to the main boat breaker on the switch? Or completely bypass the switch? Another question is it ok to run dual pro charger when engine is wired directly to battery?

[EuropeanAM]

ENGINE cables direct to cranking battery. Not nearly as worried about accessory leads as they probably won't prevent you from getting home.

Yes on the charger- was done that way for many years.

[Leebob]

My 2014 does it, even after a few new batteries. Clamp style batt. connectors, nylon lock nuts, no disconnect switch.

[Toby]

I disconnected my motor lead from the on/off/jump switch, also disconnected the leads to jump off trolling motor battery. Everything is now direct to main battery. This solved 3 problems for me. No hesitation on starting motor, no more interference on front graph when running trolling motor, and more consistent voltage to console graph. I think my on/off/jump switch was a big problem in my case.

[boboh110]

I'm experiencing the same problem with my new to me 250 pro xs. I went from a 225 EFI. I went to local mercury dealer and bought the battery he recommend. Took it out 1 evening trip and it was fine. The next morning it was in the 30's and bam!!!! Wouldnt start. Jumped it off and it was fine the rest of the day.

[Jtreed99]

I’ve never had mine not start even in the teens. It’s just slower.

[Binder]

I believe these jump switches are a big problem. I’ve taken one apart and very surprised how small the contact surfaces are in the switches. 900 DC amps on such a small contact surface must cause a significant voltage drop. I’m going to take Don’s advice and remove mine.

[boboh110]

I bought the Napa group 31 now gotta figure out a way to make it fit. I’m honestly thinking I’ll go to group 24 trolling deep Cycles since I have 36 volt. I’ve never came close to running trolling battery’s down