Merc Otbrd 115 Sputtering and Stalling at low RPM's

[Pkelly]

I have a 2002 Mercury Outboard 115 EFI 4-stroke that sputters and stalls when I bring the throttle from high to low/idle rpms. To avoid it, I have to bring down the speed really slow. Or sometime when I'm at low idle speeds it will sputter and stall. New plugs, thermostat, and fuel/water seperator filter. Any advice?

 

[sxmerc]

Re: Merc Otbrd 115 Sputtering and Stalling at low RPM's

Two items that I have seen with these motors. 1. Dirty IAC pintle, or IAC is not functioning correctly. 2. Dirty fuel injectors. Test the IAC first. Hope this gives you a place to start.

 

[bassman123]

Re: Merc Otbrd 115 Sputtering and Stalling at low RPM's

Any of you guys still out there dealing with this problem on the four stroke bogging down and sputtering. I called my local dealer and he suggested cutting off the last inch of the fuel line where the pump bulb is to see if the inside is corroded and sure enough all kinds of crap was in there flaking off. I used the bulb to pump out the rest of the fuel and I was amazed at how much of that stuff was breaking off and coming out. The tech said it was the inner lining of the fuel line. He suggested a new fuel line that is ethanol resistant, new fuel filter and cleaning the VST filter and running an enjector cleaner through it. I'm wondering if all the fixes these guys were doing kept coming back because of the fuel line. But at least I think I know what is causing the problem. It is in the shop now, I will let you know.

 

[Golfguyyyy]

Re: Merc Otbrd 115 Sputtering and Stalling at low RPM's

~~~Hi Bassman123, you still out there? - Golf here, brand new poster as of this AM, 1/21/12.
Not sure this will help but go with me cuz I had a 2007 115 hp Merc sputtering problem and resolved it. :>)

(QC - might you recall others with the exact prob. I had and if I posted here in error, my apologies, but if so maybe you can reroute it to that forum(?)

I don't know what years Mercury are the same BUT I have a 2007 115 HP outboard Mercury bought new w/the pontoon boat in 09 [2 yr leftover-great deal]. Was running perfect until late summer 2010 - It was sputtering and on occasion, stalled. Was bad up to 3000 rpm then would seem to get better. Then, the very next day out it did the same at ANY rpm, really bad, constant sputtering/spitting. I took cvr off, looked but saw nothing wrong. It was [is] under warranty, I called Mercurcy tech support who suggested I get it to the dlr. Merc support had an idea of what it was, some Turned out to be an internal hose that you cannot see, fell off!... [you might know better what I'm referring to cuz I never saw them actually take it apart to fix it but], under the main cover, in with the wires, injectors etc... there is some kind of a small cover that covers up among other things, a rubber tube/hose as I was told. THAT HOSE was falling off of its nub/connection! To the point that it completely fell off most likely that SECOND day I try it, when it ran bad all the time.

The first rough day I'm guessing the hose had PARTIALLY worked its way loose but was on enough that it was not sucking too much air or whatever it does... then the 2nd day, under normal use and vibration, it finally came loose and completely fell off.

Does this make sense in your cases? I hope so. Nothing worse than a beautiful day on the lake and your boat runs like doodoo :>) Regards, Golf
(I WILL look under my cover again next spring an dsee if I can see that small internal cover. Cost me $160 tow both ways since don't have trailer :>)