confused

steven88venture

Seaman Apprentice
Joined
Jan 28, 2009
Messages
45
Ok i have a 87 150 gt johnson and i am having a issue with well i dont know what the issue is i got it not long ago and it wouldnt run due to carbs i did a full cleaning with kits and new gas with a inspection of reeds and carb sync but now # 1 and 2 plugs are getting very black and i know its not carbs cause i swapped that carb to the bottom but the issue didnt move i dont know what else to check oh and compression is perfect on all 6cyl
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: confused

Will the spark jump a 7/16" open air gap on a spark tester ??
 

dwco5051

Commander
Joined
Sep 14, 2008
Messages
2,452
Re: confused

Does that engine have the butterfly chokes and not primer injection? If so have you ran it with the silencer off and observed that the chokes are operating together? Just a guess but it may be a problem with the choke linkages not permitting the top carb's choke to open properly. It may seen right when operating the choke with the engine off but a problem with the linkage may permit it to suck shut with air flow. As I said just a wild guess but easy to check and rule out.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: confused

It is either running rich on the top two cylinders or you have weak spark on the top two cylinders. Have you done a compression check. You may have a mechanical issue.
 
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