Re: Old Rude and Atwater: Compression?
Those are a couple of collector outboards. That said, there are many of them still running out there. If you check compression, you'll want them to be over 50 psi, but they'll be dry and you may get less, with improvement once you get things lubed up. a 13/16" socket should work for both, although the old Evinrude may have plugs in it that need a 7/8" socket. You can get some sort of sense of compression just by pulling the things through a couple of turns with the rope, and that may be all you need to know. You can feel the compression. You won't get good readings on a dry engine, especially one that's been laying around for a long time. If, by some chance, the owner has them in running condition, it won't matter. If they run, the compression and spark are OK.
More important to you will be whether they have spark. If they have compression, but no spark, you'll be hunting hard for parts. You can check for spark after pulling the plugs by attaching the wire, then grounding the plug on the cylinder head. You should see some spark at the spark plug. If it's not there, you're going to be in for some work.
In my opinion, $75 is quite a bit for non-running versions of these oldsters. They're not worth a lot more as runners. No spark? Walk away. No compression you can feel? Walk away.
The folks at
www.aomci.org are happy to answer your questions about older outboards like these. There's an Ask a Member forum there, and lots of people with lots of experience.
Finally, if you're looking for an outboard for regular use, I do suggest you look for something more recent. The mid 50's Johnsons and Evinrudes are easy to find parts for and are more reliable that those two old-timers will ever be.
One last thought: Years ago, after I got my very first boat given to me, I found a 1928 Johnson outboard with two opposed cylinders at a garage sale for $10. I took it home, mixed up some 16:1 fuel mix and dumped it in the tank. I closed the choke, wrapped the rope around the flywheel pulley and pulled. It started on the first pull. I used it for about 3 years without doing anything to it at all. I found something lighter in weight, and sold that Johnson to another guy for $20. Wish I had it back.
