1988 200 mercury black max (oil injected) idle problem

[jaker88]

1988 200 mercury black max (oil injected) idle problem. I had my boat out twice this year, 2 good runs, ran premium fuel, hit 70 mph a couple of times at 5500 rpm, trailered the boat took it home.. sat at home for 2 weeks and the battery was dead when i went to use the trim, bought a new battery, took it to the lake and it will only run on elevated idle with the little tab on the shifter up, as soon as you put the tab down to put it in gear it dies.. any suggestions would be greatly appreciated!

[perfmarine1]

Possible carb idle circuit clogged. Or idle control module went bad.

[jaker88]

Thanks for the response, so first thing you would do is take it to a marina to get the carbs cleaned?

[perfmarine1]

Thanks for the response, so first thing you would do is take it to a marina to get the carbs cleaned?

No first thing I would do is take them apart myself and clean them.I do it for a living. If you are not comfortable doing that then take it to a marina and have them fix it don't tell them what to do it may not work and you will have to pay anyway.

[jaker88]

Ok thanks, is there a specific things I have to do when cleaning them, my dad has cleaned carbs before but never on a boat, would it just consist of taking the bowls off and spraying inside with carb cleaner or would you need a needle or pin too?

[perfmarine1]

Just spray carb cleaner through all orifices and jets and make sure it comes out the other end. If the idle tube is clogged I use a single wire from a wire brush to clear it. Make sure all carb butterflies close tight and open at the same time.

[CharlieB53]

Why did the battery go dead? Was something left ON? Did the rectifier/regulator burn thru shorting and allowing feedback into the stator, turning the charging coils into heater coils, ruining the high speed windings?

Test the old rec/reg to ensure it does NOT have continuity both directions.

DVA test the high speed side of the stator to ensure the ignition is hot enough to fire the plugs at higher RPM.

And like already mentioned, clean the carbs, if adjustable idle jets be sure to count the turns in to lightly seated before removing so you can put them back to exact same position, it will save a lot of time later.