91 Johnson 25hp

[gundoc2003]

Having na issue with this engine. A few years back i was told the negative battery post melted (as if the battery reversed polarity.
I have replaced Charge Coil, and power pack (stator tested out) resistance checks on coils, new plugs, pump rebuilt, and carb cleaned (a few times).
Will idle fine, when advancing the throttle (in gear or without) the engine start to surge(hard/sharp drop in power) as a rev limiter is kicking in. and causing the engine to hard miss. once i return the idle back down some, the engine will return to a smooth idle. any help would be appreciated,

 

[boobie]

Put a timing lite on it when it's acting up and look for black spots. They will indicate an ignition miss.