Johnson outboard stalling at high rpm

[Geno1267]

Got a 1996 johnson 112 spl outboard that starts fine and runs good at full throttle for about 15 - 20 min. Then motor cuts out almost to a shutdown then I will not run over 1500 rpms. Have notice water dripping from bottom of the head on left side. Think the head gasket may be bad. Could this be causing my problem. No water on spark plugs on that head.

 

[jakedaawg]

I think your slow system is activating. I think the 112 had it. Is the alarm horn sounding? Does it beep once at start up?

 

[emdsapmgr]

A 112 engine in 20 shaft length only came with the low output alternator. Possible that only the 120/140 V4's that year had SLOW. Weak ignition components tend to fail once the engine warms up to normal operating temps. Maybe 15-20 minutes after starting? When the engine bogs when warmed up next time, check all 4 plugwires for spark. You may be losing spark to one or more plugs. Spark-gap tester works well in this instance. A cyl-drop test is also good-if you don't have the tester.

 

[johnsen90hp2002]

I have a 2002 johnson 90hp does the same exact same thing got it out of shop they cleaned carbs new plugs ran great one trip next trip after about 15 minutes bogging down bad high speed fished for awhile did the same thing later on

 

[ondarvr]

A leaking head gasket from the cylinder wouldn't show up like that, there is a water jacket between the cylinder and the outside of the motor where you see the leak, so the leak you see is from the water jacket. Check spark to each cylinder when it acts up. Is the fuel tank vent open?

 

[emdsapmgr]

Is the leak coming from the head or the head cover?