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02 Johnson 115 Cutting Out

winbub21

New member
Hello all - My first post here, so please be gentle (;)). Got a 2002 Johnson 115 (J115VLSNF) attached to an 2001 Aquasport Osprey 175. I usually run the boat once a week and almost starts right up on 1st of 2nd turn but not more than 5 turns. Idles a little rough but runs pretty well at lower RPM but when I get past the no-wake marker and go to accelerate it cuts in and out (not really a "bog" - but a clean/jerky cutting in and out) but eventually get to about 4500 - 5000 RPM... and then cuts in and out just randomly. I back off to 2000 RPM and it mellows out - no cutting out... try again to and does the same thing. I did notice after about 30 mins or so running at lower RPM (cruising) and then going to WOT it ran smooth - no hesitating/cutting out. Seems to be getting worse though every time I go out.

I've got the boat at home now and pulling apart (see pics). Inspected the fuel lines an notices some looseness so going to re-zip tie using the marine/fuel zips. Also, after priming I noticed some leakage in a few spots near carbs and below fuel pump. Upon further inspection found a screw had come loose on one of carb bowls - about half way loose. There just seems to be fuel seepage at carbs and around hose below fuel pump. At one point I noticed a squirt of fuel after priming and starting but didn't catch exactly where it came from. Could this be the cause of this cutting in-and-out during acceleration and at higher RPM? New fuel and additive and also change out spark plug cables as I noticed the bottom two were NOT snugging up like new ones would (not getting the full 'click-in' when attached to plug). Also change oil water sep this summer (change it every summer). Plugs look good. Rebuilt carbs with the standard BRP kit summer of 18. I see guys mention power pack is bad - fuel pump is bad - float is stuck - high speed jets clogged - just trying to narrow down to easy stuff before tearing off carbs again and rebuilding - which I am afraid this is where I'm going...

Thanks in advance for everyone's input -
 

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Trouble shooting 101-----Run with a timing light on each cylinder one at a time.-----Observe the light when motor falters.------That will help you determine whether it is a fuel or ignition problem !
 
Thanks racerone. Again, newbie here... but the problem only occurs when accelerating and at 3/4 to WOT. So, could some looseness in the fuel system be the cause? Like loose carb bowl screws, loose fuel lines, etc? I did notice some of that and good amount of fuel leaking out to the cowling. Shouldn't have any of that, correct?
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