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2007 90 hp 2 stroke misfire at idle

9

951carmine

New member
i have a 2007 90 hp 2 stroke 1b513442 outboard that has a misfire at idle that is worse when it is cold. it blows out a puff of smoke and some times stalls but runs pretty smooth at high rpm's when its warm it barely noticeable. i have owned the boat for 2 months so i dont know its history. i have changed 2 sets of plugs which come out black. i live on a small lake so 90% of the time that i am running it is between 1500-2500 rpm. i am very familiar with 2 stroke jet ski motors because i used to race the pro tour but this is my first outboard motor so i am not familiar with the common problems with outboards and any help would be appreciated.
 
no takes on this one? the miss seems like a corroded wire end to me. are the plug wires changeable on mercury outboards? on the jet skis the wires were glued into the coils and i would cut them back a bit and reinstall the plug boots. also the motor is in a bass boat and when i fish for a while (about 10 mins) and go to restart the motor it will start and stall after a couple of seconds. this seems to me like it is loosing the fuel in the carbs and i will have to choke it again and it will fire up. any info would be appreciated
 
I had a 2002 90. It was a hard starter first thing on the outing. Once lit, it was easy the rest of the day. I realize that only having my boat out every couple of months, hindered first starting abilities. I have posted recently on here and elsewhere about under certain conditions, running with a hotter than recommend spark plug.

Running as you are, which is how I run most of the time can benefit from a higher heat range plug (proven). I run NGK as that's what's in the service manual as standard plugs for that engine and my current 115 of the same engine design. My listed heat range is 8...the number in the plugs part number. You might check my reply to a posting herein, just this morning about another person having fouling problems while trolling. I detailed my activities there. Surely it will benefit you.
 
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