Other Uses for Lawnmower Engines?

heliocentric asks: "I recently cleaned out the garage, and discovered that I am the proud owner of 4 working lawnmower engines. Considering I neither have kids, nor am I one myself, the Go Cart idea which was quick to come to mind, left just as quickly. I'm wondering if the Slashdot community might have some good plans for some spare 5HP lawnmower engines (preferably links to plans as well as ideas)? I am a fan of the junkyard wars as well as BattleBots and all those like them as well I consider myself decent with the welder etc.. But I don't want to make something to harvest hay nor is there local Battlebot group so I am open to other ideas. Think big, think small, but please keep it legal."

Comments

What to do with a lawnmower engine? Everything.

[driftingwalrus]

Anywhere you need motive power, a lawnmower engine is just what you need. First, I word to the wise.

You're not going to find plans for the interesting stuff. Most of these machines are REALLY simple, and really require very little in the way of design to make one that works. Plans are for the uncreative. If you're stuck, go to howthingswork.com and look it up. From there, apply the rule of Farmer's engineering: If one inch in diameter is good, two inches is better. Build it good and heavy.

I also wonder, since when is it illegal for an adult to build and operate a go-kart for himself? ATVs are basically souped-up go-karts, you know. Remember, used bicycles usually sell for $20 and are a great source of drive and steering components. One thing I should also mention, a previous poster mentioned using an alternator to build a generator. One problem: Alternators need a DC voltage present to produce a field inside them. If you just run the alternator with a load and no other source of power attached, it won't work.

Next, you have make sure the engines run. I'm going to assume they're Briggs and Stratton vertical shaft engines. You need a mount for safety reasons. Get a piece of plywood, a jigsaw, drill, and some bolts(I think something 3/8" will fit in a B&S base). First you need to make a hole in the plywood that's about three inches in diameter. Drill and jigsaw it out. Now, center the engine over the hole and drill holes for the mounting bolts using the holes in the engine base as a guide for the drill. Bolt the engine to the plywood, and screw the plywood down good and tight to the work bench, or secure it through some other suitable means. Put some gas in the gas tank and take the air filter off. There's a 1" opening underneath. You need to manually choke the engine to make sure the gas is sucked into the carburetor. Hold you hand over the opening while you crank the engine. It should now start, once it has take your hand off the air intake and let it run for a little while before you kill it. If they all run, great, you can get on to building something.

If not, smell the hand that was over the air intake. Does it smell like gasoline? If not, it's likely that the gas line coming into the carb is plugged and you'll need to clean it. Some turpentine should clear out any deposits. If your hand does smell like gasoline, take the spark plug out of the engine. Smell the end of it. Does it smell like gasoline? If not, you need to remove the carburetor and clean it. If so, you need to examine the spark plug. Is the end encrusted with crud? Are the electrodes dirty? If so, clean them up with a wire brush and some emery cloth. Now you're ready to check for spark. Keep the spark plug wire connected to the plug, and hold the plug's metal base against the body of the engine while cranking. You should see a spark. Make sure that you have good electrical contact with the base. If you haven't got any spark, it's best to go buy a good book on small engine repair as you will probably have to remove the flywheel to fix the problem.

Okay, now that you have the engines all running. You can build something. Bicycles, motorcycles and old photocopiers are great sources of drive components. Motorcycles use good and stout drive chains and sprockets, if your local scrappie gets motorcycles, they are deffinitely worth scavenging.

Right now, the only thing that limits the possibilities is creativity. You know, when I was helping to teach a machine shop class I used to tell people something that would really stun them. If you can work machine tools, weld and have a good knowledge of electronics, you can build just about anything you can imagine.