I need some help. I have a 1999 40hp Johnson. I have been slowly but surly solving issues since I bought the boat and motor. My issue is it is hard to start when in water. At home on the hose this motor takes one revolution and she is started and will set and idle all day. In the water it starts hard and dies a lot. Also low rpm seems shaky but doesn't die. according to tack Idle is right at 800 which should be more that enough. Also sometimes when you do a small throttle change it is slow to respond or will gain rpm after 10 seconds or so. Otherwise this thing runs like a clock. I have redone all lines and fuel pump. Took off VRO and mix gas in tank. Had carbs sonic cleaned and rebuilt by a pro. New plugs. Spark test is very good. replaced top covers on carbs as these are known to warp and mine were. I have resynced all throttle and timing to factory specs. Replaced the rollers on linkage. ( check these on yours, it's easy to miss. plastic gets old and falls off roller. this throws everything off.) Compression is right on, on both cylinders. If you pop the release and give it just a touch of throttle w/o it going in gear it will start right up and idle fine. I am at the end of my rope on this. something is off, and I can't find it. The main issue is it dies on me when coming to dock or trailer at the worst possible time.
