1990 Mercury 90hp 2 stroke backfiring

[mkash]

have a 90hp 3 cylinder that is backfiring thru the exhaust. Also have to fully open throttle for it to start. Checked compression, engine timing with dial gauge and timing light and everything is within spec. pulled reeds and measured them a couple were .012 but were in good shape otherwise. Anyone with any suggestions?

 

[MH Hawker]

A sneeze or back fire is a normal sign of a lean condition. OR old plugs that need to be changed in a 2 stroke.

 

[mkash]

replaced the old plugs and made the backfiring more pronounced. it is not sneezing thru the carbs it is out the exhaust.

 

[undone]

Check for a sheared flywheel key.

Never mind, you said you checked the timing.

 

[enginepower]

Is this something that started all of a sudden, gradually or a new to you boat/engine? Go here: http://www.cdielectronics.com/support/ to check the integrity of your ignition system. Make sure the trigger wires are hooked up properly and make sure coil wire ignitor wires are hooked up to proper coil.