Rough idle

[Dawgs226]

1998 Johnson 130. Boat seems to run great at wot. But when I'm idling it seems rough and stalls. And also at low rpms the motor shakes as if it missing somewhere. I connected a spark tester and all 4 plugs have spark. I don't know if it's me but it looked like port side plugs sparks are a little weaker. I performed a test. While running I pulled the plug wires off one at a time. When I pulled either strbd side plug wire the motor sputtered and died right away. When I pulled the bottom port side wire it seemed a little worse but didn't die. When I pulled the top port wire the motr didn't change at all

Any ideas?

[Dawgs226]

dont know if this has anything to do with it but it seems to smoke (white smoke exhaust) a little more than it should

[Dawgs226]

and its smoke not steam

[boats.net]

You should first complete a compression tests, post your results. If good, while motor is at idle, spray silicone spray through the throat of each carb, note the motors reaction.

[Dawgs226]

silicone spray? whats that?

[boats.net]

It is a lubricant, like WD40, but silicone based.

[Dawgs226]

I'll try it.......any specific brand?

Heavily spray each throat or lightly?

[boats.net]

One shot, either it will pick-up or die out. If it picks up, you are having fuel problems in that cylinder, if it dies out that cylinder is working.

[Dawgs226]

Can you tell me what spray I should ask for?

[boats.net]

No specific brand, just ask for silicone spray lubricant.