Ignition timing issues

Hi, I have a 1988 Nissan NS90A Same as Tohatsu M90A. The engine has been sitting for 3 years. I rebuilt the carbs with oem rebuild kits. I completely cleaned every port and passage. I did the link and sync as per the factory manual. In the manual, it says that any engine coming out of long term storage should use a tank of gas at 50:1. I cleaned the oil reservoir, put all new oil lines on and purged the oil pump. I am using Yamalube 2M 2 stroke oil. When I started the engine, it has a lean sneeze. will pop, and a puff of smoke comes out, then catches up to itself. I noticed fuel pouring out of the bottom carb. I took it apart to find the brand new float was full of gas. I thought I found my problem. I put one of the old floats back in after fully cleaning the carb again. I did the same to the other 2 carbs. Floats were fine but I took everything apart and cleaned them again. Reinstalled. Did a link and sync again. Same results. I get a lean sneeze. I checked the plugs, they are fine. They are brand new. Calls for b8hs10. I have br8hs10 in there.  <br> The manual calls for 5 degrees after top dead center. If I hold the plate to 5 degrees BEFORE tdc, the engine runs great with no sneeze. I am really confused trying to figure out why it sneezes. Will double oil cause this? Using a resistor spark plug? After going over the manual again, it says to use 89 octane fuel. I didn't realize this and am running 87 right now. I don't think that would cause it, but maybe I am wrong. I want to put the boat in the water and go for a ride, but I don't want to burn a piston or do any damage. Any help or suggestions would be great. Maybe this engine just runs that way? Thanks to all for reading. By the way, the engine runs great at higher rpms. Just not at idle.  Compression is at 120 for each cylinder also.

If carburetors have low speed mixture screws then open them 1/8th turn at a time.----Perhaps the sneeze will go away.-----Timing on outboards is fixed and normally needs no fiddling.

87 octane is OK. Resistor plugs are fine. Idle timing isn't that critical. As racerone suggested, perhaps go through verifying idle mixtures.

Racerone, setting the timing per the the manual is easy. A couple of measurements of the rods and adjust the stops. Manual says 1 + or - ¾ turn from seat. I tried setting them all to 1 turn out and ¼ turn increments OUT but not in. What is the best way to set these screws? Seat them all, and back out ⅛ at a time? Paul, you mention that idle timing isn't that critical. Would a sneeze be acceptable at idle then? Can I safely put this thing in the water as long as there are no lean pops at higher rpms? Thanks guys

I usually start with pilot screw at about 2 turns out.

Lean sneezing / miss at idle has nothing to do with timing.------Lean sneeze is much miss-understood.----So I would concentrate on carburetor / low speed mixture issues.

racerone said:

Lean sneezing / miss at idle has nothing to do with timing.------Lean sneeze is much miss-understood.----So I would concentrate on carburetor / low speed mixture issues.

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Do you start adjusting from the seated position? Does turning them in or out lean or enrich the mix? Thanks for your reply

goodforbrains said:

Do you start adjusting from the seated position? Does turning them in or out lean or enrich the mix? Thanks for your reply

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Clearly you are not familiar with carburetors. Start lightly seated, then open counterclockwise to about 2 turns. Further adjustment is done on the boat in the water. Adjust idle stop to specified rpm, then readjust mixture for highest speed, then readjust idle stop. Once satisfied, richen about 1/4 turn for stability.

Hi Paul, thanks for your reply and sorry for the delay. I am familiar with carbs to an extent. I just wanted to be sure that I was adjusting them correctly. Multi carb sync is where I was struggling. Anyway, I got that lean pop taken care of. Like many of the threads that I read, people swear that they cleaned their carbs thoroughly, but didn't. I fall into that category! No matter what I did adjustment wise, the lean sneeze at idle persisted. So I took the carbs apart again (3rd time) and cleaned them. This time I blew compressed air through them after cleaning. Linc and sync, adjusted idle jets. Engine idles great now. Dropped in water for a trial... new problem presented itself. I will make a new post for this problem. I truly appreciate all of your help and the patience all of the technicians here have, especially answering redundant questions over and over. A sincere thanks to all of you guys!

Glad it's working so far.