Logo
FULL SITE MENU

2004 Merc 115 hp 2 stroke misfiring and stalling at idle

K

kmkeeney

New member
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​
 
Re: 2004 Merc 115 2 stroke misfiring and stalling at idle

If this is a 2+2 model it only runs on the top 2 cylinders at idle.---------------Start with a compression test-----------Then check that you have spark that will jump gap of 7/16"on all 4.--------------If fuel sits in the carburetors for long periods of time it may clog the jets and will require claning.
 
Re: 2004 Merc 115 2 stroke misfiring and stalling at idle

Thanks for the reply! It is the 2+2. I checked the compression before I bought the boat in September and they were all dead nuts 125 psi. About the only way I know to check a spark is from working on my old blazer when we used an indicator light. I assume the procedure is the same? Or is there a special process / tool for outboards?
 
Re: 2004 Merc 115 2 stroke misfiring and stalling at idle

What is the compression TODAY---------------There are special tools available to check spark, with adjustable gaps. You need to confirm strong ignition / spark.------------------Or run it with a timing light hooked up to see if it is ignition related and which cylinder is missing..
 
Back
Top