Home › Forum › Ask A Member › 9.9 Johnson Carb Question › Re: 9.9 Johnson Carb Question
After spending 3 years on my 76 here are my thoughts on these older carbs..I have had to set the float level slightly higher with the aftermarket plastic floats for the idle to be right on these first carbs. It would lean stall when throttling back. I wonder if the cork and plastic floats are actually equivalent. I got this tip from a member here I think.. The following story is for my 15hp but might be of some help..
I took out some cam lift from the beginning to about 3/4 or just where the cam starts to curve up. Not sure what cam you have on that 9.9..I can’t see how there can be a smooth transition from fully closed to just opened. So I set the roller at the vary beginning of the cam to just have the carb barely opened. I soldered the 2 holes closed on the butterfly and filed a flat on the top of the butterfly as the later ones have. It now runs better than ever. Even the wife commented about how smooth the motor runs when docking and such.
When I first got this motor 3 years ago all apart in a box it had a piss poor carb setup with it. I have spent hours on that carb..looking at ebay pics of carbs and looking at every carb exploded view I could for these motors. I have had it apart I betcha 20 times in 3 years and have made many changes that were a step back..