Johnson 200 HP High altitude adjustment (Rough idle & stalling)

[Jpalyo]

I recently purchased a boat with a Johnson 200hp outboard. 1991 model J200TXEIB. It ran great in Denver but when I brought it home to a nearby lake at 7500 feet it runs rough at idle and stalls. Is this an carburetor adjustment issue or re-jetting for high altitude issue?

 

[fireman57]

Sounds like you need to clean the low speed jets n the carbs. Have you checked spark with an open air spark tester? They need to jump at least a 1/2" with a blue snap. Orange spark is too weak.