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45 HP 1986 MERCURY MISFIRE

kmakela

New member
"MY ENGINE IS NOT RUNNING ON T

"MY ENGINE IS NOT RUNNING ON THE TOP 2 CYLINDERS. I INSTALLED A NEW SWITCHBOX LAST SPRING AND IT RAN FINE AFTER INSTALLATION. I AM GETTING SPARK TO THE 2 PLUGS BUT THEY DO NOT SEEM TO FIRE OR ARE OUT OF TIME. CAN THE TIMING GET FOULED UP ON THESE ENGINES? (I AM GETTING GASOLINE TO ALL CYLINDERS, PULLED OFF BOTH CARB BOWLS.)THE PLUGS ARE NEW."
 
Need a bit more info on motor

Need a bit more info on motor year hp ?. what is comp. how far will spark jump ?

arcrat
 
IT IS A 1986 45 HP. HAVE NOT C

IT IS A 1986 45 HP. HAVE NOT CHECKED COMPRESSION BUT I THINK IT IS OK. THE LAST TIME I RAN IT ABOUT A MONTH AGO IT WAS LOADING UP AT IDLE BUT REVVING WOULD CLEAR IT AND COULD GET FULL SPEED. THE SPARK JUMPS AT LEAST 1-1/2 INCHES.
 
"spark, compression, carbs, no

"spark, compression, carbs, no skipping test. I would do a cyl drop test if that all passes, which it probably won't.
http://www.themarinedoctor.com/cgi-bin//YaBB.pl?num=1144247599

The only other thing that hasn't been mentioned would be a reed problem. But fuel would be spitting back out the top carb if the top cyls are dead.

Were the main jets cleaned in both carbs or just the bowls removed. Without any gas to the cyls with the bad carb they get no oil."
 
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