98 4.3 Mercruiser Miss

[Farmer Paul]

Hope I can get some help with my 4.3 ...I have a 98 Starcraft Islander 2001 with 4.3 Mercruiser ...The Boat has never stayed in water overnight , always stored indoors ..It is a low hour boat..2 year ago it started with an occasional miss / to be more correct it is like the ignition is shut off for just 1 second ...The Engine runs smooth , lots of power ...Just that momentary shutdown ...It might happen once an outing usually when running around 3000 rpm . This year it is doing it randomly but every minute or 2 .

I have checked electrical connections , they look good ...Can it be the ignition coil gone bad or possibly the ICM .

Any help is greatly appreciated !

 

[Eric 3.7LX Alpha 1]

A bad coil doesn't act that way, at least in my experience, they either work or don't.
Efi, Mpi, or Carbed?
Post the serial number of the engine.
How long has it been since it's had a tune up? Distributor cap, rotor, plugs, spark plug wires?

 

[Scott Danforth]

Welcome aboard.

go thru the TB ignition troubleshooting tree in the stickies at the top of the sub-forum.

if you have the older 2-wire ignition trigger, that design was replaced nearly 20 years ago with the updated 3-wire design.

check that.

 

[Farmer Paul]

A bad coil doesn't act that way, at least in my experience, they either work or don't.
Efi, Mpi, or Carbed?
Post the serial number of the engine.
How long has it been since it's had a tune up? Distributor cap, rotor, plugs, spark plug wires?

This old Girl is carburetor.. wires cap rotor plugs less than 5 years old ...maybe 40 hours on it total