Re: 1981 Evinrude 9.9hp 2str starts but won't run
When rebuilding the carb you may have missed some very small debris in the air/fuel passages. On the many outboards and motorcycles, both 2 & 4 stroke that I have had, about the leanest low speed needle adjustment was 1-1/2 turns out. Suggest you try it there for starters, maybe going richer until it starts to stumble a little then back in just until it smooths out a little. If it is not a mixture problem there is likely an obstruction from the tank forward. I had the same motor but can't remember the linkage set up. A good shop manual should show the proper set up. Maybe the float is stuck shut or not adjusted properly? I had a carb on a Honda 2HP that got plugged up. I cleaned out but it never ran perfectly until I gave up and put a new carb on it. Let us know what you find.
All of this assumes you are getting a nice fat bright blue or white spark when grounding the plug out of the motor?and pulling it over.
Last edited by dabnis; 08-13-2012 at 12:22 PM.
Reason: Additional info