F250 cold start question

[striper311]

Hello all,

I have twin four stroke 250's on my boat. They are 2008's. Ever since they were new, when it is cold(below 40 degrees or so), they will idle low(3 to 4 hundred rpm's) and a little rough for a few seconds before winding up and idling at their warm up speed(around 900 rpms). Once they rev up, they run perfect. Both engines do it, and by and large only do so when it is cold. I am assuming the cold start map doesn't account for these very cold conditions.

Today, I noticed that one of the engines didn't want to rev up. It slowly gained speed until it was idling at 800 rpm's(took about 20 seconds), but it just wasn't running right. I gave it a moment, and as it was still not running quite right, I shut it down and re started it. Once re started, it ran perfect. My question is...once I re started it, I went to the back of the boat and I noticed a fuel slick around the back of the engine. I was a little concerned, but after thinking about it, I am thinking the engine was running rich(cause of rough idle) and when it re started, it passed some of the unburned fuel out in the exhaust. Would this make sense? I ran the boat right after this, and it ran perfect from idle to WOT of 6100 rpms. Fuel burn was normal.

Thanks for your help.

[Sparkieboat]

these motors are run off of a ECU with several sensors..I have found them to be somewhat imperfect to say the least...I am kind of new to the EFI out board world..but I already miss my Carbs..I had a 1979 Johnson 115 that cranked, idled and ran out great and gave me very few problems..all of which I was able to fix myself for low cost...so far in my short exploration into the land of EFI, I have already had to take my motor to a dealer..(my first experience with this).I havent got the bill yet..but I bet it will hurt.

[rodbolt17]

your motors are broke.
FIX THEM.
EFI is EFI
just like your car.
it starts and runns correctly from -50 to +150 degrees with the turn of the key or its simply BROKE.
after dealing with EFI/DFI for the past 15 years, carbs simply SUCK.
any mechanic that says otherwise is simply an untrained monkey.

[Sparkieboat]

why all the carb hate there Rod??? I know why Rod likes EFI..cause he gets paid to fix them and business is good, I heard that Rod is buying a vacation home in the Bahamas and is part of the conspiracy to do away with all carburetors..I am just joking..but i am seriously not happy with the cost and the level of difficulty related with EFI/HPDI diagnostics...I mean you say "get it fixed" but I have 4 kids and live off of a very limited income so $1000-3000 repair bills hurt me very bad, just saying...... as far as comparing to a car..I drive Hondas..never had any problems..i wish outboards were any where near as reliable as my car.
hope you all have a great day

[rodbolt17]

and most likly your honda is
is
is
is
EFI.

EFI works very well, very easy to test and troubleshoot and way more efficient than carbs.
most techs still dont understand how fuel is moved in a carbed set up.
they are completely lost with a pressurized fuel set up.
EFI works and works very well and its easier to trouble shoot than carbs if you understand why things do what they do and what effect each subsystem has on the other.
thats where reading comprehension actually comes into play.
you have to visualize many things happening almost at once.
and remember, the electronics are always waiting on the mechanicals.
basic articulated rod gasoline fueled engine.
suck, squeeze, bang and blow.
everthing else just helps it go.