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Johnson aggressively stuttering 109 seconds after startup

T

tzuffante

New member
I cant get it to run longer then 10 seconds!

2003 Johnson J150PXSTM 150 hp

Just bought and already replaced fuel pump, filter and carbs

Watch this video to see what is happening:
My boat failing
  • The use of the primer solenoid helps the engine run longer before stuttering, so clearly a fuel issue
  • adjusted the carbs and cleaned them with no success
  • fuel bulb is always hard and filters are good
  • new gas
  • All plugs have spark
Seems to be the carbs not delivering enough fuel but regardless of how I adjust them I cant get it to run without stuttering, the only thing that helps is turning the red lever to the starter solenoid to directly inject some fuel. Even that does work forever though.

Any ideas or Tips?
 
Well you not doing it any favors by not have it hook up to water, impeller is likely kaput now. Running it with the hood off in bright daylight will also cause problems as it effects the optical eye on ignition. That motor has Quickstart and it wont idle smooth till it reaches 95°.
 
faztbullet said:
Well you not doing it any favors by not have it hook up to water, impeller is likely kaput now. Running it with the hood off in bright daylight will also cause problems as it effects the optical eye on ignition. That motor has Quickstart and it wont idle smooth till it reaches 95°.
Click to expand...
I hooked up to water you just can’t see it from that angle. Don’t worry lol. The temp sensor for a Quickstart broke so it’s unplugged. I believe they’re just thermal couples with an over temp switch built in. I read it another forum that it’s not needed, You just have to do the quick start procedure manually by letting it warm up slowly. Maybe I’m wrong, do you think the prom could be electoral?
 
tzuffante said:
The temp sensor for a Quickstart broke so it’s unplugged. I believe they’re just thermal couples with an over temp switch built in. I read it another forum that it’s not needed, You just have to do the quick start procedure manually by letting it warm up slowly.
Click to expand...
No, the temp sensor is not just an over temp switch. The PowerPack gets live data from sensor and advances the timing by 10* to increase idle RPM while the engine is cold and once the sensors hits 105*F it idles back down. Quick Start is active on each start cycle, but as if the temp sensor reports above 105F the feature is disabled and immediately drops back to base timing.

I'd suggesting fixing the temp sensor problem since that is a known issue, then move forward with troubleshooting.
 
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