1991 Evinrude 25 hp cold starting issue

I recently sold this motor to my brother. I've owned this motor for over ten years and has always worked great. I always stored it in the garage during the winter and it was winterized. This past Spring, I pulled it out and put it on the boat to get it ready for my brother. He bought the boat from me. I pumped the fuel bulb up, then pulled the primer lever out two or three times and left it out and began to trying to start the engine. I cranked and cranked and it never would start. It acted as if it wanted to but just wouldn't. I sprayed a squirt of starting fluid in the intake and it started right up and it continued to start easily after this. It seems like it can flood itself out when priming the cold engine instead of busting off. My brother now has it and is experiencing the same issue. It almost feels as if the primer going to the carb isn't working properly. I believe it's supposed to engage a "cold start enrichment circuit" when it's left partially pulled out.

Can someone give me some things to look at to troubleshoot this? I can see fuel squirting inside the carb when I pump the lever but it doesn't seem to help. The end result of this issue is eventually flooding the engine and having to wait.

How long has it been since the Plugs were replaced

Plugs are less than a year old. Clean as can be other than when you flood it trying to start it.

Try pushing the primer back in after the 2nd pull out. Each pull will inject some fuel as you mentioned. If you leave the knob pulled out, the circuit remains open and will continue to feed fuel while cranking. It may not need that much fuel on a cold start, this time of the year.