98 mercury EFI 200 burnt piston

houndawg

Cadet
Joined
Aug 27, 2004
Messages
17
Hey guys i have a 98 mercury 200 efi that that burnt/melted cyl #1 piston,other cyls look ok,
i had ran at 5500 for approx 1 mile when it happened,no alarms & did not seem to overheat,
melted edges of piston down to rings,any common problems on cyl#1 on these? or any suggestions
where to look for cause? Also anyone know what the finish # or grit of stones for cyl walls will need
to be? thanks
 

wired247

Lieutenant Commander
Joined
Oct 8, 2011
Messages
1,557
Re: 98 mercury EFI 200 burnt piston

Its common with EFI's. Injector gets plugged and the cylinder goes lean. Have all the injectors cleaned before you get it back together.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,590
Re: 98 mercury EFI 200 burnt piston

Also have the ECU tested, about $225 to test and have injectors cleaned/flowed and balanced by Brucato...
 

Dukedog

Captain
Joined
Oct 6, 2009
Messages
3,235
Re: 98 mercury EFI 200 burnt piston

Also anyone know what the finish # or grit of stones for cyl walls will need
to be? thanks

This would be whatever your machine shop does ta fix tha broke hole......You can do like some will suggest and try ta clean it up yourself but you'll be back ta square one sooner or later if not done tha right way....jmo

Will add besides gettin' tha injectors cleaned you need ta check ALL tha 'lectrics startin' with tha idle stabilizer/control or whatever they called it in '98. Ya check it by "throwin' it away". Yours wouldn't be tha first that its destroyed. They're worthless........
 
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