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2002 johnson 70hp 4 stroke efi bogging down under load

ccrippen

New member
my outboard motor has been having an issue of starting fine and idling for a couple of minutes but then stalling. New plugs in it every year with normal maintenance and only rec fuel used. The motor always starts right back up after stalling. I have never had an issue while driving the boat and even while idling if I bump the throttle up slightly it will run all day with no issues. That has been going on for a short period of time but hasn't showed any other problems. Now, when under load the engine will bog right now and misfire. It still idles fine and when not in gear, I can rev it up to 3500 rpm (rev limiter when not in gear) and it runs just fine. I had about half a mile of driving to the boat launch to get it to the trailer and it started to smooth itself out. I originally couldn't get it over 1,500 rpms under load, and I got it up to 3,500 while in gear and it was up on plane just fine. I pushed it a little bit and the sputter was still there at around 3,800 rpm so I backed off to make sure I made it to the trailer but I feel like had I kept going, it would of smoothed right out.

I am suspecting the fuel vapor separator is possibly dirty as I did pull both fuel filters and there was quite the color difference in them. The high pressure filter fuel looked like it was varnished, hence why I am suspecting a dirty fuel vapor separator. I called local marinas to see if they would scan codes for me and of course they want to diag it and charge $ and they are a couple of weeks out. We are currently in the market for a newer tritoon and I want this one fixed asap so we can sell it. Any help would be appreciated!
 
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