The AM Forum

I'm trying to help my nieghbor get his yard chipper going and am having no luck. He's a good guy and I like heiping him out...him and his wife never complain about my huge antenna looming over there property and he has helped me with a few antenna projects.

It has a 11 hp Tecumseh engine with no spark. I pulled the housing off to check the magneto and points but it has no points just the mag. The engine kill switch is ok and I tried it cranking it over with the kill wire pulled off the mag just rule that out, no good. We tried a new spark plug of course. I figured well the mag must be bad so he bought a new one and I put it in today. No spark! I adjusted the gap between the mag poles and the flywheel to about .010 inches per data if found on the internet.

Am I missing something obvious? The ignition system has 2 parts and I replaced them both, plug and mag, the flywheel magnet is rusty but still grabs a screw driver blade pretty well. Is the magneto gap very critical?

Any suggestions would be greatly appreciated.

Steve
WA2TTP

Take some steel wool or fine sandpaper and remove the rust from the magnet then try it.  I had the same problem and that was the solution.  Good luck

magneto coil might be shot!

Most mags I've seen have to have that "kill" wire to ground to fire.

73DG

Some small engines have a low oil level sensor. It prevents the spark if oil level is too low. Check oil level, fill if needed.

-Don

All of them that I've dealt with need that wire to be lifted from ground to work, if it is grounded then it is shorting the spark to ground

Most flywheels have a  "sheer key" that alings the firing position.
Change it. It does not have to be sheered to cause no spark.

I concur on the above but use sand paper only. Steel wool will stick to the magnet.

Thanks for the input so far.

I did install a brand new magneto.

I did sand the flywheel poles but there still pretty pitted from rust. This chipper is stored outside year round covered with a tarp so it gets plenty of moisture.

I did a brief test today before the storms hit with a neon bulb. I connected it between the spark plug lead and the head and it does flash when I rotate the flywheel with my hand but that doesn't take much voltage and it wasn't that bright. This may not prove much.

I'll be playing with it again tomorrow or Friday.

Steve

If it light the bulb you got spark!

And if it "got spark" and if it "got fuel" then the timing is next thing to check.  Then valves.

In a case like this I'd remove the plug, leave it hooked to the magneto lead and ground the body of the plug, then crank and watch for spark in the actual plug. That will tell you if you have sufficient voltage at the plug.

Great test, thats exactly what I do.  I also have a spark tester that allows you to vary the space between two electrodes to determine how much spark it has.  Bottom line is the spark at plug.  Some newer motors have a coil and electronic ignition circuit.  Those can go bad also but from what your saying its not that new to have one of them. 

Joe, GMS   

Check for a stuck valve...does the cylinder have compression with the spark plug in?

I understand the guy who owns the chipper is married. Be careful. You could be charged as an accessory.