1977 mercury 500 50hp fuel?

[dickjackson]

1977 merc 500 50 hp no fuel to top cylinder has 120 lbs compression all 4 cylinders. i have rebuiltcarbs replaced all fuel components, and replaced switchbox due to lack of fire to the top cylinder i now have fire but no fuel. clueless!!!

 

[CharlieB]

Re: 1977 mercury 500 50hp fuel?

Is the carb filling with fuel?

The primer bulb should fill the carb, unless the float is hung up and the needle does not open.

Hold your hand over the mouth of the carb when cranking, attempt to seal it off, can you feel any suction?

Is the spark plug getting wet or staying dry?