72 Johnson 6hp tuning question.

[tiggertat55]

good afternoon, I have a trip planed to the convict lake area in California. its about 8000 ft in elevation. the last time there, i attempted to run the little 6hp it would run for a bit then die. i would like to troll this trip. do i need to change the jetting or is it all in the low/high speed adjustment at the front of the engine? i have the factory service manual and it makes no mention of high altitude service. i also have not been able to find any other jets other than stock. any help or info would be helpful. the motor runs fine at home, at about 2000 feet.

thanks for you time.