96 Johnson 30 hp idle

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cdn_traveller

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Hey I have an outboard that I haven't used in about five years. I just redid the carb and tried to adjust things.

It runs but doesn't idle well. It pops and shudders and almost stalls

Check this

https://youtu.be/5P7Ms1uiIlk

https://youtu.be/k3a90Kp7HZE

Any advice would be appreciated.

Thanks
 
Set yourself up with the motor in a barrel.. the extra resistance against the prop exhaust will change the adjustment.
 
I replaced the plugs, coils look ok but I will pull off to be sure. I will try to dig up a Barrell and rig that up.
 
Do you have a set of plug wire pliers? Pliers that you can pull the cap off the spark plug while the engine is running?
If you do, pull pull one plug wire at a time and see which cylinder runs the engine smoothly on one cylinder. Sounds like you have a coil arcing to ground or a plug wire arcing to ground intermittently. If you do find this then you can swap plug wires first and see if the issue follows the plug wire. Swap coils next to see if it follows the coil. Check for cracked coils if you have them off.
Not that you do not have a mixture issue but I do believe this one is ignition related.
 
Well I went out tonight but it was too late to run the outboard. Looks like a bad plug wire though, I tested the wires with my ohmmeter and one was bad.

I guess I should have tried that sooner.


Will get new wires Monday and try again!


Thank you all
 
It is a very primitive way to do it but you can run one of those at night or in a dark shop and if they are arcing to ground many times you will see it. Of course there are plenty of places they will be doing it that you can't see. But I have also seen motors that you could take the cowl off at night and it would look like a fireworks display. LOL
 
So I replaced the cables. It seems to run a little better but is smoking more than I thought it did. Also I think I should increase the idle speed a bit? Given it stalls or wants to stall when I put in gear?

https://youtu.be/N44Qx70dtzI
 
Lean the engine about 1/8 turn at a time then wait for 20-30 seconds and let the engine react to the change in mixture. Keep doing this until the engine sneezes lean then richen by about 1/4 turn. This should get you into the ballpark. Do this before you adjust idle RPM as this will make a difference in RPM. It should increase when leaned. What is your fuel/oil ratio at the moment?
 

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