Instructables

Can i install (rig up) a pull start on my 18hp riding mower?

I know that they dont make pull starters for large hp motors because you would have to pull really hard, BUT i am willing to pull really hard. :) My starter is messed up and i dont want to spend a fat stack of cash to fix my 18 hp murray rider. I know i will be able to rig up a connection between any pull starter and my mower, but the question is "is this a bad idea, and will it work?" I have also heard of using a drill and socket to start your engine, but i dont want to do this because when the engine does start, it will turn faster than your drill and mess you up! i have been having problems with burning out the switch that is wired to the starter. SO finally i removed the switch entirely and tried to start it by touching the wires together and it made a "snap" inside the machine (not around the starter) and now it doesnt try to start anymore. The battery currently reads 12v and the switch wires also show 12v. There are no fuses inside the mower. I dont know what to do!

bestburglar4 years ago
Ring or email the mover wreckers for support and cheap parts. They do postal orders too.
http://www.hotfrog.com.au/Companies/Mower-Wreckers
cgosh4 years ago
Oops -- In case you custom make your new brushes, the top of a new brush sits a tiny fraction of an inch below the top of the spring-loaded cage. As the brush wears, the spring lowers into the cage.  Eventually, the spring runs out of travel and won't press the brush against the commutator any longer. Brushes usually fail in "spurts" (on-again, off-again, changes with temperature, etc.) so it gives you warning time to fix it, and also lets you know what's failing.
cgosh4 years ago
Push-start it, or use a homemade strap.

First up is the old "put it in second gear, have a rider press the clutch, push it (downhill is easier) by hand, slide out the clutch, then push the clutch once it's running" routine.
You can do this by yourself, but it's tricky and hazardous -- you'll have jump on, press the clutch and shift into second while it's coasting.
Wet grass, loose gravel, or using first gear just locks the wheels up. Third gear may or may not spin the wheels fast enough.

Really old lawn mowers simply cut an angled slot into the edge of a pulley on the end of the crankshaft. You slipped the knotted end of a rope in the slot, wrapped the rest of the rope around the pulley and gave it a yank. The knotted end slipped out of the slot.

If your generator pulley has a flat outer surface (some do, some don't), I used to have a simple hand pull-starter for 60 hp Volkswagen Beetle engines in case of a dead battery. It was a 2-foot length of narrow, flat leather strap with a short rivet or screw poked through one end and a simple wooden dowel handle on the other end. Any strong, flat strap might work, but leather grips to itself.

I'd cut off one-third the width of an old belt and scuff up its smooth finishes. Twist a screw into one end and file down the length and the threads to keep it from getting stuck in the pulley; that would be very bad once the engine starts.

Drill a small matching hole in the flat of the generator pulley (rather than the slot required for a knotted rope), insert the rivet just to give it a place to start winding, wrap the strap around the pulley a few times, and give it a yank. The generator pulley has a belt that spins the crankshaft pulley to spin the engine.  Small engines without a battery have no generator, they use a magneto, much like Model T Fords had.

Install a new spark plug while you're in there. People throw out perfectly good mowers every day just because the plug is worn or dirty.

In the meantime, disconnect the ground connector on the battery, remove the (extremely simple) starter motor and disassemble it.
Usually, the only problem with small motors (and simple generators -- they both work the same way) is the length of their carbon brushes (black, square-ish dirty posts with a braided wire and a connector on one end that sit inside a spring-loaded cage) have worn down and no longer touch the commutator (all those little flat metal plates on the spinning part). Unscrew the connector, lift the spring and remove the brush(es). I have a local "import auto electric" repair shop that sells starter motor brushes for $5 a pair.

If you can't find the right size, get a pair that's a little too large and file them down - they're just soft carbon, sort of like a giant pencil lead. That's why they wear out.