2001 johnson 150hp miss

bassone

Seaman Apprentice
Joined
Nov 2, 2010
Messages
39
2001 johnson 150hp that has a miss at low rpm's, called the shops around here and they are two weeks out and i have 2 tournaments coming up that i can't miss. motor runs very strong once i get around 1700 rpms, but has a miss at idle to 1700 rpms, sometimes it dies and is a little hard to start, changed plugs out, the old ones had alot of black on them but the new ones didnt help also checked compression and was great, just had a complete powerhead rebuild about six mounths ago, just dont want the huge cost of a rebuild again. any ideas? one person told me it sounded like a cam sensor, thanks for your time and help!!!!!
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 2001 johnson 150hp miss

Just guessing but it could be the OSI sensor or a bad pack. Pull one spark plug wire off at a time when it's acting up and see if you can narrow it down to one cyl or more. If you have a timing light, put that on each cyl and look into it. If you find black spots, that's the cyl that's missing.
 

bassone

Seaman Apprentice
Joined
Nov 2, 2010
Messages
39
Re: 2001 johnson 150hp miss

Thanks! I don"t guess i understand what you mean about the timing light, could you explain it a little better? Thanks again for your help!!!
 
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