2005 Merc 115 2 stroke misfiring and stalling at idle

[kmkeeney]

I'm having trouble with an apparent misfire and stall at idle. Every time it misfires, the RPM's drop and it sometime stalls out. If it keeps running, it coughs alot of smoke after each misfire.

Wondering if anyone has seen something similar. I'm thinking it's an ignition problem? Got all new plugs, but that didnt' solve the problem. Maybe new cables or coil are required? Maybe service the carbs?

Any input would be appreciated!

Kevin

 

[jerryjerry05]

Re: 2005 Merc 115 2 stroke misfiring and stalling at idle

Check for water in the fuel.Serial# and model needed.Profile???Jerry

 

[1nebel0]

Re: 2005 Merc 115 2 stroke misfiring and stalling at idle

Clean and fresh fuel is a must today...Every boater should have a racor water separator on their boat given the effect of Ethanol...With that being said, you need to do a number of things first...Compression, as everything begins with good even compression. Secondly, a spark testor to test the qualifty of all of the cylinders..Lastly a DVA meter with peak voltage adapter to start testing switch boxes, stator, and trigger...you can do a cylinder drop test and if you find the cylinder that isn't contributing like the others, then you can switch the coils out from another cylinder to one see if the miss now goes to another cylinder or if it stayed on the original one...A manual is a must and I always buy the shop manual and not the after market one.. If you are going to own a boat you have to invest in tools, manual and time....If not you need deep pockets to find someone to fix it for you...Good Luck

 

[CharlieB]

Re: 2005 Merc 115 2 stroke misfiring and stalling at idle

The 4 cyl 115 is a 2 + 2 carb design. EPA emmission regs dictate a reduced idle emmissions, Merc managed to meet these by idling on the top two cyl's only, the lower two carbs do not have idle complete idle circuits and do not pass enough fuel to fire at an idle.

Carb cleanliness is always critical to maintain fuel flow thru the idle circuit. Mineral accumulation will restrict fuel flow until the mixture becomes lean enough that a 'Lean Cough' begins to occur.

You MIGHT temporarily adjust the idle mmixture screws out (CCW) 1/8 turn, if the additional fuel improves the condition then you can be sure that a complete carb cleaning is needed in the very near future.