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Please help fix my 99 115 Johnson

D

deckboat

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My 99 johnson 115pleem has been running worse and worse lately. It started where it would just start sputtering every now and then, then it got worse and worse. When it starts acting up we will go from cruising at 4300 rpms to it breaking up and spitting and running horrible and not go above 3000 or so. It will some times rev back up for a second like nothings wrong then rite back at it again. This started happening for a minute or two at a time now its getting worse and worse. last two times i took it out it started doing it 1 minute after i left the dock i kept running it last time and it eventually stopped breaking up and ran good again on my way back. today it was acting up then just shut off wouldnt restart. after a couple mins sitting it would start and run for 15 seconds or so then turn back off. got back to the dock and wouldnt even start again. Tried hand choking it and no difference. Brought it home parked it went out tonight to test it and she fired up and was sounding beautifull again. So far i have replaced my fuel water seperator, my primer bulb, fuel pickup in the tank and cleaned the carbs a little with some carb cleaner. could this just be carb related. i bought a spark tester today and set the gap on it at about 1/2 inch and it fired cleanly across on every cylinder. ( i tested this back at the dock when it wouldnt start) im lost, hoping a veteran can chime in so i can get her running rite for the summer. Thanks in advance p.s. also replaced the spark plugs yesterday with the ones recommended for it the old ones were black and nasty and i replaced them around september.
 
When issue comes up again on the open water,bring a timing light with you to see if she's losing spark on a cylinder, The issue could be an electronic component breaking down from excessive heat,coils, stator, then cooling down and running well again until repeat of issue CDI Electronics has a great troubleshooting manual online for the proper procedures,might need a multimeter!! But before doing this ,run a compression test on every cylinder. Has the engine ever been decarbonized??
 
I checked compression over the weekend and am at 128-130 all cylinders I haven't decarbonized yet but I did test for spark last time it was acting up and it was firing good could it still be my ois sensor or something else and how would I test that. I do have a millimeter but no timing light
 
When its running, is it spitting & "sneezing" almost like a small backfire? Hows it run at idle, especially in the water, not on muffs? What about WOT? Running okay WOT?
 
it has been idling good it kind of spits though I just thought that was because it was a 2 stroke but it will idle all day with no problems. but when I get on it after about 30 seconds it was acting like it was starving for fuel you could say idk about coughing or sneezing just spits and sputters and acts like I has some really bad gas it will randomly starting running again wide open for a second or two then rite back to sputtering. and sometimes it clears up and doesn't do it again for the rest of the day but lately it has been getting worse and worse. I ordered 4 carb kits so hopefully that's a good start. and it will only run for a little bit at wot at cruising speed it goes a little longer before acting up
 
When you do the carbs make sure you clean the high speed jets in the float bowls.
 
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ya when I cleaned them out I didn't understand where the high speed jet was until after I put everything back together. is the low speed jet the one on the outside of the carb housing that is visible on the carb
 
rebuilt that carbs and cleaned them really good using my blow gun attachment on my air compressor they didnt look bad but there all done and i wont have to worry about that part now. Getting ready to head to the ramp and test her out hopefully all is well. Ill keep everyone posted and thanks again for the help
 
nothing wouldnt even start on spraying into carbs i have fuel going into every carb now so i know its not fuel related so i called the mechanic. he will be here in 3 weeks ill post what it was to hopefully help someone else out in the future. thanks for trying to help though it was worth a shot
 
turned out to be water in the gas i felt so stupid. the guy pulled out almost 2 gallons of water out of my tank which is only 30 gallons. now shes running beautifull. he drained some fuel from the line into a cup and you could see it was 90 percent water at first
 
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