91 8hp Evinrude broken bolt

I am missing one of two bolts on either side of my anode below the exhaust.
I ordered and picked the bolt up yesterday.
It only goes in 2/3 the way, and will not start to thread in.
I've attached pics.
Question is: do I take lower unit off to confirm broken bolt, or do I drill with lower unit in place, and use easy out to back broken bolt out?

Does the other bolt come out easy?----Drilling bolts out in aluminum is never easy without a drilling fixture.----Those " easy outs " can you in trouble.----Best way is to remove lower unit I think and some sort of drilling fixture to keep drill from wandering.

racerone said:

Does the other bolt come out easy?----Drilling bolts out in aluminum is never easy without a drilling fixture.----Those " easy outs " can you in trouble.----Best way is to remove lower unit I think and some sort of drilling fixture to keep drill from wandering.

Click to expand...

Yes i loosened the other bolt so it will come out.
I'm not a mechanic yet it makes sense to pull it apart and not do it blind.
The fixture for drilling makes sense if there's not a stub to grab hold of thanks for reply

I've got the prop off, the spark plugs disconnected, the shaft turned by hand and moved into forward. I've removed the other bolts (2 more), I've drained the gear lube, all per the seloc manual I just purchased. The next move is to pull straight down to remove gearcase from mid section. This does not happen. I have a gap maybe a 32-16", and no more. What is my next move from here? Thanks (from this model's parts diagram, and the manual instructions, there isn't a shift rod clamp to remove a bolt from. I'm in a pinch here. )
I received a Mac's River Runner prop guard to install, but want to be sure this bolt is repaired before installing the prop guard. I'd think hitting stuff with a bolt missing would create more problems than with all 3 in place tight.
Thanks again for all the replies and info. I'm very new at this
Jeff