Merc 18 5995557 Main Jet Size or Carburetor Float: You Be the Judge

[JDusza]

My Merc 18 is running rich at high speed, too much fuel.
Clears itself at WOT and then repeats; gets to choking up a little, then clears out and screams, repeat.
Main jet measures 0.002 above stock @ 0.054.
Is main jet worn out from use, and letting too much fuel in?
So, try to find a main jet or re-set the carb float?
Thanks,
J

 

[Faztbullet]

Re: Merc 18 5995557 Main Jet Size or Carburetor Float: You Be the Judge

Have you done a plug reading???? Symptoms like this can also be a ignition problem..

 

[Barnacle_Bill]

Re: Merc 18 5995557 Main Jet Size or Carburetor Float: You Be the Judge

The jet is fine. They get dirty and clogged up but they don't wear out. Have you rebuilt the carb?

 

[JDusza]

Re: Merc 18 5995557 Main Jet Size or Carburetor Float: You Be the Judge

Not sure what a plug reading is, but, I am pretty confident in "over-fuel".
Spark will jump 7/16" air gap.
Compression is high at 140 each.
When idling at the dock, she'll eventually choke up, blowing blue and eventually clearing out at throttle up.
Why would I have a 0.054 jet when largest stock on BOM is 0.052; It is a Belgian engine...
I have not completely rebuilt the carburetor. I am reusing the gaskets. I have gone through the jetting.
This thing screams when hitting the sweet spot.
Thanks,
J