20hpmercury
New member
Rebuilt a number of Mercury's, but this one has me baffled.
Got a 1994 90hp 3cyl 2S that the previous owner rebuilt the powerhead.
I replaced stator, trigger, voltage reg, switchbox, coils and plugs and plug wires with CDI
rebuilt all 3 carbs per OEM manual, main jets .062/.064/.062
compression is 129/130/126 cold with throttle plates WOT
rebuilt fuel pump, new hoses, swapped fuel supply twice, no change
adjusted idle mix screws, no change
ck'd TDC of #1 piston with dial indicator and it matches the indicator
DVA +coils at idle is 180
oil injection is disconnected
pulled reed plates off, reeds look ok and hole to fuel pump is open
set timing to 20deg BTDC at 3000rpm in fwd gear
tried 19p and 21p props, no change
If I set the throttle cable for the plates to be WOT, it will bog about 5200rpm, if I set the throttle cable for the plates 3/4 open, it all runs great and maxes out at 5200rpm
Starving for fuel or ignition??
Any suggestions would be much appreciated.
Much Thanks.
Got a 1994 90hp 3cyl 2S that the previous owner rebuilt the powerhead.
I replaced stator, trigger, voltage reg, switchbox, coils and plugs and plug wires with CDI
rebuilt all 3 carbs per OEM manual, main jets .062/.064/.062
compression is 129/130/126 cold with throttle plates WOT
rebuilt fuel pump, new hoses, swapped fuel supply twice, no change
adjusted idle mix screws, no change
ck'd TDC of #1 piston with dial indicator and it matches the indicator
DVA +coils at idle is 180
oil injection is disconnected
pulled reed plates off, reeds look ok and hole to fuel pump is open
set timing to 20deg BTDC at 3000rpm in fwd gear
tried 19p and 21p props, no change
If I set the throttle cable for the plates to be WOT, it will bog about 5200rpm, if I set the throttle cable for the plates 3/4 open, it all runs great and maxes out at 5200rpm
Starving for fuel or ignition??
Any suggestions would be much appreciated.
Much Thanks.
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