2 months ago I could hardly spell "lathe" but I wanted a new hobby, so I found a lightly used, but broken 7x12 on craigslist for $200 with some tooling, bought a replacement board from LMS, and started making swarf. The internet is a great place to find ideas and how to's so I started searching. I came across Joe Websters free 4 stroke plans: http://home.comcast.net/~webster_engines/
... and I was off.
I first made a bolt... and was pretty proud of it, then a little wobbler, it worked well, but I wanted something that made fumes.... so I started on the Webster. Luckily there is a Metal Supermarket 4 miles from my house so I purchased the raw stock needed for the Webster and started turning.
The cylinder and piston were first, then the head. It was fun over Christmas to show my friends and family what I had created. Everyday I made another piece and I got a little closer to "first pop". It happened on January 9th, after 8 build days in the shop.
All the parts shown with the exception of the bearings, plug, bolts, ignition coil, and finned flywheel were made from scratch, some based on the basic plans. I did not want to go the points and condenser route because of the luggage you have to haul around in order to run the motor. I had found a dead weedeater on the side of the road 2 years ago and I tossed it in the "to be used someday" pile. I works VERY well and I plan to use this type of ignition in the future because it is so reliable and cheap.
The vapor carb is based on Jan Ridders idea, but completely designed and built by myself. I used a carb off my old RC10 GT nitro car and it worked ok, but was a pain to adjust and not reliable, so I use the vapor card exclusively now. I can adjust the mixture with a turn of a long nut that covers and uncovers a hole on the intake tube.
I am currently running straight Coleman fuel with a few drops of marvel mystery oil, but have used nitro methane, denatured alcohol, 87 oct gas, butane, propane, rubbing alcohol, and mapp gas (stinks...). the coleman fuel can be run in the house for short times and it has a pleasant odor like I am camping...
The ignition timing can be adjusted by moving the coil up and down thus changing the spark from 20 degrees BTDC to 20 degrees ATDC. A neat effect of this is that you can adjust the idle from 1000 RPM to 4000 RPM just by changing the timing.
It will start with a swift turn of the flywheel, but this gets old quick so I installed a one way bearing and nut from an old RC rope starter and I can use my drill with a 12mm socket to start it. It just takes 1 or 2 revolutions to fire and then revs to full RPM.
I might add a rope starter pulley and a PTO pulley some day, but for now I am done with modifications and am starting on Jan Ridders OTTO engine.
This is a pictorial of the finished parts....