1993 20 hp mercury bogs down at full throttle

[hungupcity]

I’ve got a 1993 20hp mercury motor that has fire to both plugs, will idle but kinda sputters like it’s not a smooth idle, and will run half throttle, but when you go to throttle it full speed it just bogs down. Seems like it’s not firing right?

Ive checked the basics.

Checked the bulb on fuel line and also the fuel tank vent.
Took carb apart and cleaned carb. ( wasn’t dirty)
changed the plugs and checked gap. Used a inline spark tester to verify spark to both cylinders.
Did compression test when motor was warm and both are getting 120 psi. 100 psi when engine is cold.
Took coils apart and inspected for any damage.

Should I take fuel pump apart and inspect it?
Could it be a switch box problem?
Should I get a timing light and check my timing at the fly wheel?

Thanks in advance.

 

[flyingscott]

Try pumping the primer ball when that happens, if it fixes it it is a fuel pump issue.Clean and rebuild the carb with a good quality kit.

 

[hungupcity]

I have tried that and it doesn’t change anything. I’m thinking this evening I’m going to take the fuel line loose from the carb and see if it would be pumping fuel from the fuel tank?

 

[flyingscott]

The fuel pump is part of the carb on that motor. Look to make sure all the linkages are in good shape and none of the plastic bits are broke. You also want to.make sure the throttle is opening all the way