2004 Mercury 9.9 two stroke help.

[pzmaria]

Recently I have purchased a Zodiac and it came with a 2004 Mercury 9.9 two stroke motor. The motor was seating in a garage for over two years so I expected it would need some work. Changed the oil, changed spark plugs, clean the tank and hoses. Removed carburator and took it apart. Soaked in carburator cleaner overnight and blew all orificies with compressed air. Removed reed valve and all was good. Set air mix as per book ( 1 1/2 turn) and played with it back and forth. Checked the ignition timing and all is good. Compression is good too. For some reason the motor has uneven working pattern when idling and once engaged lower rpm is creating a stall and puff of smoke every 5-10 seconds, then return to normal and another stall again and again. Any ideas where is the problem? Below there are two short clips how this motor works.
Any input will be greatly appreciated. Thanks to all members.

https://www.youtube.com/watch?v=KJBG5RDxcXk
https://www.youtube.com/watch?v=6KCNWwyjdyU

 

[racerone]

Put a timing light on it and see if there is steady flashing.

 

[QBhoy]

Check for tiny holes on the diaghram skin.

 

[flyingscott]

Did you rebuild the carb with a complete gasket kit? Did you put the carb base gasket on correctly?

 

[QBhoy]

Ignition system breakdown would do that too. Maybe look at testing the wee coil and output from the wee stator and rectifier.

 

[flyingscott]

Rectifier has nothing to do with the ignition on that motor. And that motor would only have a rectifier of it had a charging system.

 

[QBhoy]

Pretty sure it does Flying Scott.
It would be very unlikely that engine didn’t also have a charging outlet. Most engines like that from 8hp (maybe even the 6 too) have it. I have 2 similar aged 8hp in the garage. They both have a small charging outlet.
interupted power to the coil would certainly cause a miss fire.

 

[QBhoy]

Ah. I might be wrong about this. Not sure. Yamaha and mercury....doh. Wrong outboard section !!!! I’m off to bed, before it gets worse !

 

[racerone]

???----Lots of those motors running without a rectifier !----And most ignitions on those Mercury motors do NOT NEED A BATTERY OR RECTIFIER to make the spark.

 

[flyingscott]

Pretty sure it does Flying Scott.
It would be very unlikely that engine didn’t also have a charging outlet. Most engines like that from 8hp (maybe even the 6 too) have it. I have 2 similar aged 8hp in the garage. They both have a small charging outlet.
interupted power to the coil would certainly cause a miss fire.

For one thing he op has a 9.9 not a 6/8 hp motor. You probably have OMC motors which are not the same. The mercury motors use a straight charging system because they are easily converted to electric start. The charging system on Mercury motors is a stand alone system nothing to do with the ignition.

 

[QBhoy]

Read comments above guys.