Lawnboy with no spark

Ronsotto · 05-25-2009, 04:45 PM

Ok, so here it is…… I’ve never, in my 51 years, met any brand, make or model of small engine I couldn’t get and keep running…… UNTIL NOW.
I have an almost mint condition self-propelled 2 stroke Lawnboy model 8073. It has that emergency flywheel brake and electric kill switch.
It ran fine last year but this year it won’t even kick - no spark at all. Tried a new plug and still nothing!
I have tried disconnecting the kill switch wire, lightly sanding the minor surface rust on the flywheel magnets, cleaning both coil pick-ups and mount surfaces, re-set the air gap to EXACTLY 0.010” and the plug to 0.020” and still no spark.
I have exchanged the coil and plug from my brothers known good running Lawnboy and still no spark on my machine. Put my old coil and plug on HIS machine and it runs fine so I know the coil and plug are good.
Is it possible the flywheel magnets are too weak to generate enough current for a spark? Any piece of metal touched against either flywheel magnet still has lots of attractive force so I don’t think that’s what’s wrong but I’m stumped and now grasping for answers.
My lawn is so tall now I need a map just to get to the back shed. I’m ready to trash the mower and buy a new one!
Any suggestions?

**octaneman** · 05-25-2009, 11:14 PM

Hi Ronsotto

If it is equiped with an electronic ignition module, then the module may have gone bad. Here is a diagram I found.

The module is number 44 on the diagram.

k2skier · 05-26-2009, 02:10 PM

If the engine you swapped coils with wasn't an "F" engine there may be a compatibility issue. You said you removed the small shorting wire from the coil and retested; correct? When you test for spark you must use the rewind, you can't spin the flywheel fast enough by flipping it by hand. If you do both of the things I mentioned, and you still have no spark, the coil/module needs replacing.

05-25-2009, 04:45 PM	#1 (permalink)
Ronsotto Registered User Join Date: May 2009 Posts: 1 OS: xp	Lawnboy with no spark Ok, so here it is…… I’ve never, in my 51 years, met any brand, make or model of small engine I couldn’t get and keep running…… UNTIL NOW. I have an almost mint condition self-propelled 2 stroke Lawnboy model 8073. It has that emergency flywheel brake and electric kill switch. It ran fine last year but this year it won’t even kick - no spark at all. Tried a new plug and still nothing! I have tried disconnecting the kill switch wire, lightly sanding the minor surface rust on the flywheel magnets, cleaning both coil pick-ups and mount surfaces, re-set the air gap to EXACTLY 0.010” and the plug to 0.020” and still no spark. I have exchanged the coil and plug from my brothers known good running Lawnboy and still no spark on my machine. Put my old coil and plug on HIS machine and it runs fine so I know the coil and plug are good. Is it possible the flywheel magnets are too weak to generate enough current for a spark? Any piece of metal touched against either flywheel magnet still has lots of attractive force so I don’t think that’s what’s wrong but I’m stumped and now grasping for answers. My lawn is so tall now I need a map just to get to the back shed. I’m ready to trash the mower and buy a new one! Any suggestions?

05-26-2009, 02:10 PM	#3 (permalink)
k2skier Registered User Join Date: Sep 2008 Location: Oregon Posts: 313 OS: XP Home-SP3 My System	Re: Lawnboy with no spark If the engine you swapped coils with wasn't an "F" engine there may be a compatibility issue. You said you removed the small shorting wire from the coil and retested; correct? When you test for spark you must use the rewind, you can't spin the flywheel fast enough by flipping it by hand. If you do both of the things I mentioned, and you still have no spark, the coil/module needs replacing.