lovedr79
Well-known member
2009 mercury 20 hp 4 stroke. can idle all day long, runs fine for about 15-20 minutes then goes to about half power. no missing, no sputtering, can limp back home. come back next day same thing. could this be a bad coil? i have one coil for two cylinders. could the coil be getting hot then the problem starts? how do i go about checking to see if its bad with a voltmeter? i tried to check the ohms with the positive lead in the spark plug cap and the negative on the coil ground wire. nothing sits on "open" "l", tried the positive coil wire same thing. for giggles i put the leads in both spark plug caps, i get .018 ohms. i would assume that i should be getting more than that. just not sure. the manual i have only goes out to year 2000. so i am trying what i can, i just dont want to buy a fuel pump and a coil and a CDI box. how would i check the CDI box? thanks again!