1986 Mercury 9.8 110 outboard

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
14,571
As stated before the motor needs"
Compression, in both the Combustion Chamber, and in the case of a 2 Stroke, in the Crankcase.
Air-Fuel delivered to the Combustion Chamber, via the Crankcase.
A Source of ignition at the proper Time
 

Mc Tool

Lieutenant Commander
Joined
Aug 7, 2024
Messages
1,716
If its popping off timing has got to be about right ....right enough to make it run .
Undo the float bowl drain and see if there is any fuel in there.
Give it about ¼ throttle , put hand over the carb inlet and pull starter ....you should be able to see evidence of fuel inside the carb . If not probly carb is either blocked jets . The fact that it pops off with fuel in the plug hole suggests strongly that you have compression and spark
Take a look at this video, 1986 9.8 mercury outboard' https://share.google/pyqTwDKmlxSp3uu5K
Link to a video to link and sync

1986 9.8 mercury outboard' https://share.google/RoyKFgl5JPYIY29ej
Hopefully these are 2 different videos for your motor
🙂
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
14,571
Compression in the Combustion Chamber, yes, but to me, the Crankcase/reeds are suspect, as the OP has sprayed fuel into the carbs, and it appears not to have made it to the Combustion Chamber to fire
 

Mc Tool

Lieutenant Commander
Joined
Aug 7, 2024
Messages
1,716
Compression in the Combustion Chamber, yes, but to me, the Crankcase/reeds are suspect, as the OP has sprayed fuel into the carbs, and it appears not to have made it to the Combustion Chamber to fire
Yeah , there is something suss going on there ....cant help but thinking about that reed block locating pin being misaligned and springing the crankcase halves 😬.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
14,571
Since both cylinders are not firing, and the odds of both sets of Reeds failing is not likely, and it appearing that Fuel is not getting to either cylinder, maybe the crankcase isn't fully closed. I think it is time to pull the Powerhead off and tear it apart and inspect. But before doing that, I would once again try to get the motor to fire by spraying Premix into the carbs, If it does fire, then likely a Carb issue, if not, time to dig out the wrenches
 
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