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2000 Mercury 2 stroke 100hp start problems... please help

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driver500

New member
I have a mercury 2 stroke 100hp 4 cylinder efi it works flawlessly once started and heated...
but when i turn the engine off, and try to re-start the starter would like hold it self from spinning and the battery goes down lower then 9v.. and sometimes it just fires right up. now i know for sure the battery is good as i tested it with a battery tester on load with 680a test... what could be the problem? please help!
also i have noticed that in between 2000rpm and 2500rpm the engine vibrates a lot seaming it would like to stall but doesnt, never stalled....
further more the engine in neutral sometimes stalls. and that in-water idle rpm is approx 1000rpm and on the muffs (hose) it idles at about 2000rpm and i ask myself why?????
this is my first boat, compression was 7 bar on each cylinder... and it has new spark plugs, also ran an engine cleaner with fuel.
and it has new petrol... it is also a very thirsty motor... please help me... thanks
 
...try to re-start the starter would like hold it self from spinning and the battery goes down lower then 9v...
Click to expand...
What does the starter do if you jump the large studs on the solenoid? Remove and clean all of the battery cables and high current start cables.
 
well it does the same thing, after jumping the starter directly i decided to dismantle the starter... i discovered that the brushes were worn out... the starter is at an electrical tech getting new brushes and cleaning the armiture. hope it solves the problems... now any idea why the engine sometimes stalls in neutral?... when i start the engine and rev it up a little bit... just a second or two then it stays put a 1000 rpms...
 
...in-water idle rpm is approx 1000rpm and on the muffs (hose) it idles at about 2000rpm...
Click to expand...
A few things come to mind: idle RPM should be about 625-650 while in gear in the water...there is an adjustment. You need a manual.
 
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