20 HP Mercury

D

Dixie2008

Recruit
Joined
Sep 19, 2008
Messages
2
I have a 1997 20 Hp Mercury outboard that runs only on the top cylinder. the carburetor has just been rebuilt. the reed valves checked okay. the cylinder compression is the same 60 lbs on each cylinder. the coils check good. the cylinder is getting good spark through the plug. ANY IDEAS ON WHY THE BOTTOM CYLINDER IS NOT FIRING???
 
Barnacle_Bill

Barnacle_Bill

Admiral
Joined
Feb 8, 2004
Messages
6,469
Re: 20 HP Mercury

Repost under the Mercury forum. Thbis one is for posting problems with the site.
 
Don S

Don S

Honorary Moderator Emeritus
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Aug 31, 2004
Messages
62,321
Re: 20 HP Mercury

Moving to Mercury/Mariner Outboard forum.
 
jbjennings

jbjennings

Captain
Joined
Jul 18, 2007
Messages
3,903
Re: 20 HP Mercury

Who rebuilt the carb and who checked compression? Why was the carb recently rebuilt? I'm suspicious and hopeful that your compression is more than just 60lbs. on each cylinder since it should have over twice that. Have you checked your spark to see how wide a gap it will jump? I'll bet it's weak spark myself. Just because it pops when you ground it to the block doesn't mean it's got enough spark. You really need a spark gap tester which you can get at an auto parts store for cheap.
 
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