I was trying to remove the lower unit in the evening. Now, in the daylight I was able to see that it was a 12 point bolt. I used a 12 point 7/16 socket to take off the trim tab and found a 9/16 nut underneath. The lower unit slid right off. No wood wedges or anything.
Once inside, I found a mess of rubber inside the water pump housing. Nothing left of the impeller blades. Inside of the housing has some rough crud stuck onto the top. So I'll order an entire water pump kit.
As the impeller exploded, I imagine some of the smaller bits could have made their way up the water pipe and into the cooling jacket, potentially plugging the outlet tube. I've ordered an old Mercury factory service manual and expect to find what I need in there, but any insight would be helpful.
I'm looking at
http://www.sterndrive.info/mercury-o..._drawings.html to identify parts.
Below part 16 referenced in the above link, the Exhaust Leg Seal Plate (correct name?) was in pieces when I went looking around. not all of the pieces are there, so I imagine they've been gone for a while. It looks like
http://www.egmcartech.com/store/Merc...651095839.html, but I haven't been able to identify that this is the correct part. Any pointers to this part would be helpful.
Edit: I found something that looks like the same, but don't know if it covers my model. It's a pn 92815 Plate, Exhaust Seal. There are a number of places (Amazon, eBay, Crowley Marine) that carry this for $10 or a little more.
http://www.crowleymarine.com/mercury...rts/465_18.cfm lists this part (#9) for a 1975.
The Reverse Lock Cam is made of plastic. The ramp surface is pretty rough and there are worn spots for neutral and reverse. Is this normal and should I be concerned?
I read about how Roberta rebuilt her lower unit at
https://www.glen-l.com/phpBB2/viewtopic.php?t=13928 and her's appears to be aluminum. This page
http://www.nlamarine.com/products/me...ant=1110590244 mentions that both plastic and metal were made. Are they universal? Looking at 43308-1 (plastic) or 43308T-1 (aluminum) (both on eBay)
Thanks for your time
David