1994 Johnson 140 hp Idle mixture adjustment??

[Blanco11]

I just bought a boat with the above engine on it. I am assuming that I need to adjust the idle mixture based on the following information. The boat can from an elevation of 3600 ft and is now being operated at 6000 ft above sea level. Here is the symptoms: The engine was checked out by a certified mechanic prior to purchase and ran without problems but now at this altitude the engine starts and idles initially but then begins to idle rough and stalls. When put in gear it dies out. If I rev the engine up it will gradually increase the rpms and seems to clean it self out. If I then put it in gear it and increase the throttle it will go and run smoothly. After running at higher rpms and then returning to idle (in gear) it will takeoff again but seems to hesitate until about 2500 rpms then revs smoothly. It runs fine at all rpms except idle.

Am I correct in assuming that I just need to adjust the idle mixture to correct this problem or is there something else that I need to check.

Thanks for inadvance for the input

 

[Monte1961]

Re: 1994 Johnson 140 hp Idle mixture adjustment??

If you have adjustable low speed jet/s, then yes you can. Motor is probably running to rich at idle. Good luck and post back