Mercury 9.8 engine miss

[Newman1415]

I have picked up an older merc 9.8, not sure of year and no serial number. I have pics, but my video won’t uplod of how it runs (tips)? I have replaced fuel pump diaphragm, cleaned carburetor and running new high test fuel properly mixed. Checked and cleaned spark plugs...not sure what the issue is but if I pull the close until it’s almost closed it runs perfect. Hence why I replaced diaphragm thinking it was needing more fuel to mix wth air. That didn’t fix it. Let me know what you think

 

[racerone]

Based on the decals it is a 78 / 79 model.----Having to pull the choke on indicates there is a carburetor / fuel delivery problem.

 

[Chinewalker]

Sounds like a fuel delivery issue. Did you just replace the diaphragm or did you install a whole carb kit? Carb fully disassembled and cleaned?

Also, high test fuel not necessary.

 

[Scott Danforth]

not sure what the issue is but if I pull the close until it’s almost closed it runs perfect

you have something plugged in your carb