6604A gearcase removal

[bjorgumbrian]

I wanted to inspect the impeller on my Evenrude 6604A outboard motor. How do I remove the gearcase from the upper unit? I removed the four bolts and it dropped an eighth of an inch. Is there a pin in the shaft? How do I access it? I appreciate any advice. Thank you!
Brian

[boats.net]

the shift shaft retainer is located under the carburetors.