1989 120hp miss and stall above 3,000rpms

Hello All new to the forum so excuse any ignorance.
I have a 1989 Evinrude 120HP on a 16ft bass boat. The engine would not run above 3,000 rpms and the boat would not plane and occasionally would stall.
I replaced the spark plugs, checked engine compression 135 psi on all 4....pulled the main jets in the 4 carbs cleaned all 4 jets, one had a little water and main jet was slightly loose 1/2 turn) so I put everything back together. While running with ear muffs a quick rev above 3,000 rpms still produced a miss like it was dropping 2 cylinders. All 4 carbs appeared to be spraying an equal pattern on a quick rev. What should i look for next? Thanks for any help

Did you overhaul carbs or just clean jets? If jets were dirty ,so was everything in carb bowl. Do not test on earmuffs.book up timing lite,run till it misses,check each cylinder.how old is gas? What's it look like? Fuel pump pressure when it starts missing?

Rwbutler said:

Did you overhaul carbs or just clean jets? If jets were dirty ,so was everything in carb bowl. Do not test on earmuffs.book up timing lite,run till it misses,check each cylinder.how old is gas? What's it look like? Fuel pump pressure when it starts missing?

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No i did not overhaul the carbs they looked extremly clean except for the one jet that came loose and had small piece of debris in it. Gas is brand new...I don't know fuel pump pressure but bulb stays hard also when pumping it is pretty tight and still runs poorly. You can see spray pattern on all 4 carbs and appear equal with copious amount of gas coming thru...it seems more ignition related but i dunno thought i would test the coils, stator, etc just not sure how to do that. It still could be a carb problem though...Thanks

I have been checking firing and bottom 2 cylinders would not light up the timing light...unit is at a point where it will barely run and sometimes not at all. It dropped fire on 3 cylinders for a moment and now the top 2 are dead and bottom 2 are firing. Checked all the resistance on the stator, trigger, and power pack all are in spec, but can't get it to run long enough to check outputs. Not sure where to go from here.

Check power pack ground wire,gently pull on it.can look good ,but be rotten on inside.

yes it seems ok Did find it might have resistor plugs in it They are ngk and have a big blue R under the numbers not sure what that means.

I replaced plugs with non resistor and now have consistent fire on 3 cylinders. The bottom port cylinder is not getting fire. Switched the coils wires etc to no avail. There is no fire coming from the power pack to the coil. Tested the wire for continuity and all good....Does this narrow it down to power pack or could trigger be enter the picture?

bumped