115 Johnson sputteringcutting out higher rpmbs

"Hi, new member hoping for som

"Hi, new member hoping for some help with a problem. I've got a 7 year old 115hp Johnson saltwater edition motor. It's carb'd model and had never, ever had any problems till last week. While cruising out to fish between 4k & 5k rpm it started to sputter/cut out, it would buck and jerk and loose power. I could see the tach fluctuate. We got it back home and started working on it. Plugs were a year old, wires too. Checked all the grounds for corrosion, pulled the coils off and the lower one was cracked really bad on the bottom. We suspected these. Ordered new coils ( 2 ) replaced them this weekend. Also replaced the plugs just for giggles, changed the fuel filter on motor, replaced spin on filter in boat, wires are only a year old. Took it out Saturday and ran great all day. Coming in for lunch started doing the same thing again. I tried pumping the squeeze ball to see if it was running out of fuel and no change. It won't get on plane when it's doing this, due to lack of power, but then it'll clear up and run great for several minutes and do it again. So it is hit and miss. Any ideas? Fuel pump? Carb issue? Hope it's not the power pack $$$$.

Thanks for your help."

"check your fuel tank for wate

"check your fuel tank for water--by,pulling a fuel sample in a glass jar and observing.if water is present,drain tank,and add a water obsorbing fuel treatment.If u find water,rem the whole sys needs to be drained,tank,fuel lines,filters,and carbs..all purged ."

"jwbmarine .. thanks for the r

"jwbmarine .. thanks for the response. I did pull the line off the fuel pump and squeezed a mason jar full of fuel out. No water at all. We then replaced all the fuel filters primary and secondary. I did go ahead and dump some HEET water dryer in the tank. Then replaced the coils, plugs, checked the grounds.
Any other thoughts? I'm open for anything. Thanks again."

"after that,i would say it nee

"after that,i would say it needs to be checked out thoroughly,...but it sounds like interrmittent ignition pack problem,quite possibly,an optical sensor problem."

is there a way to check out th

is there a way to check out the ignition modules on these? Or is it basically replace it and see? Also the optical sensor is it under the flywheel or accessible just under the plastic cover? I'm leaning toward ignition issue. It almost sounds like a top fuel bike bouncing off a rev limiter when it's happening around 4k rpm and then all of a sudden it'll clear up and take off. I hate just throwing parts at something ... just gets frustrating. I'm going to go over everything once again tonight. Thanks again.

This should be simple to troub

This should be simple to trouble shoot! Just hook up a $40.00 inductive pick-up timing light to each plug in sequence and observe the flash. A steady flash indicates a good ignition system for that cylinder.Repeat for all six ignition systems. Now if ignition proves OK then use a flash light( in carburetor throat ) and observe fuel coming up the main jets and compare you 6 fuel systems.Take a compression test first!!

sorry that should be 4 systems

sorry that should be 4 systems on that motor.

it's a 4 cyl but I get you

it's a 4 cyl but I get your drift. Good idea. Thanks.