Hi all. Bored auto mechanics instructor checking in. Had some stuff kicking around the house and decided to throw it all together. I traded a guy an air compressor for two 1960 Evinrude outboards, one was a 5.5hp and the other was a "Sportwin" 10hp. The 10hp I brought to school and am currently trying to get running. The 5.5hp had a bad powerhead and I wanted a fun little project.
I've been wanting to do this for years.
I had a brand new $250 Honda lawnmower engine lying around. I bought it for my mom's mower but apparently bought one with the wrong crankshaft size so it didn't fit. Of course, I waited too long to open the box and couldn't return it. Sooo I had to do something with it.
Off with the Evinrude powerhead, and measuring the shaft for the lower unit. I wanted to keep the gearshift mechanism. Head off
Now I had to find out how to mate the two halves. The lawnmower has about a 2.75" shaft that's 3/4" around. The Evinrude lower unit shaft has a 7/16" shaft that sticks up about an inch. I didn't want to have to cut the Honda shaft because it's some kind of hardened steel and I'm running low on cutting discs. So I took some measurements. A rear brake rotor from a GMC is actually the perfect height. the rotor disc is the perfect mounting surface for the Honda engine.
I had to cut a corner off to clear the gearshift. The Oxygen/Acetylene torches didn't want to do it so I used a cutoff wheel.
I then had to make some kind of connection between the Honda crankshaft and the lower unit shaft. I weighed my options (Welding the two together, making an adapter, etc. But I ended up drilling out the center of the Honda crank, and making it a tight fit for the lower unit. The point of no return
After some measurements, I drilled a few holes in the brake rotor and used the original Evinrude powerhead mounting holes. I had to weld a couple washers with the ole' Arc welder to make sure I had a good bite with some of the bolts. selfie?
Four bolts hold the "adapter plate" to the lower unit
It didn't come out dead center but it was pretty close. This is all backyard engineering here, you remember.
Now I had to mount the engine+shaft to the adapter plate. I did a million test fits, and found that I could only mount the engine with three bolts. Whatever.
I drilled three holes about 3/8" into the rotor where I wanted to bolt it
I got it running. I think I need to add some weight to the crankshaft or a heavier flywheel. Shouldn't be much of an issue though. I would also like to experiment with some different pitch propellers because the Honda runs at about half the RPM as the Evinrude did.
Oh, I also need to find a boat to put it on. Thanks for checking it out!
https://youtu.be/DDmwNtMyetc - 6 second video of it running.
Submitted April 09, 2016 at 10:28PM by Caravannnn http://ift.tt/1VHA1KW
No comments:
Post a Comment