1996 mercury 9.9 outboard, stalls when decelerating

woodchop

Recruit
Joined
Jan 23, 2026
Messages
1
I am re-posting this from another site...

I re-assembled the motor and ran it in a barrel. While running, I checked the stator voltage. It is steady at 85 volts and increases to 95 plus when revving. however, it still stalls when decelerating. Anyone out there have such an issue?
* I have tried another complete carb and it does the same
* I have re-built the carb that is on the unit now.
* I have checked the block for leaks and did change the O-ring that seals the output shaft
* the compression is 90 psi on both cylinders.
Bill
 

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Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,905
I am re-posting this from another site...

I re-assembled the motor and ran it in a barrel. While running, I checked the stator voltage. It is steady at 85 volts and increases to 95 plus when revving. however, it still stalls when decelerating. Anyone out there have such an issue?
* I have tried another complete carb and it does the same
* I have re-built the carb that is on the unit now.
* I have checked the block for leaks and did change the O-ring that seals the output shaft
* the compression is 90 psi on both cylinders.
Bill
Whatever your other problems are, your 90 psig on compression checks are 30# below the Merc Manuals specks for 2 stroke compression of "If compassion is less than 120 PSIG, expect problems". With that disparity, I'm amazed that it runs at all!!!!!!
 
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