Trouble shooting Merc 200 20HP

[Puzzled look]

After a carb srtip down and rebuild my engine wont run at low rpm or idle it just conks out.
It runs really well in the top two thirds of throttle range.

Heres what ive checked/done so far:

Stripped the carb down several times put in new gaskets and re cleaned
All jets are new and in place!

Stripped the fuel pump down and replaced the filter diaphragm and gaskets.

Checked the gaskets for holes...none found.

The plugs seemed to be fouling so they have been cleaned.

Has any one got any suggestions what else to check and how to do it.

Thanks

 

[corm]

Re: Trouble shooting Merc 200 20HP

Hi,

The year would be helpful so a person would know which carb is on the engine.
Have you tried adjusting the idle needle?

 

[Puzzled look]

Re: Trouble shooting Merc 200 20HP

1976, yes ive adjusted the needle.

 

[7920hpMercury]

Re: Trouble shooting Merc 200 20HP

I would get a service manual for your year, either Mercury factory or Seloc.

Suggest check your low and high speed coils with an ohm meter. Assume carb is clean and set correctly.