honda mower, no spark

[Bill Dufour]

I have a Honda vertical shaft lawnmower. it will not start, will not pop with starter fluid. I used a spark plug tester and got nothing. No visible spark even at night. I figure either a new coil or a flywheel key is sheared.
On the old points engines a sheared key would mean no spark since the magneto voltage and points opening where out of range of each other.
On a modern no points engine I think the coil would still make a spark wouldn't it? Just the spark would be out of time and no fuel mixture would be in the proper state to ignite.
I am wondering if no spark definetley means the coil is bad or could it still mean a bad keyway so the flywheel and magneto has lost time with the points, or what passes for points these days.
Bil lD

[Mac McQuinn]

Bill,
I had this happen several years back to a 1984 Honda Push mower, it ended up being corrosion on the surfaces of the flywheel/coil interface. I used sandpaper to
clean things up and this returned the spark. My shed where the mower was stored ended up with lots of water one spring, I feel the mower suffered lots of corrosion due to this. I still have the mower as a back up and it starts right up.
Good luck,
Mac

[Tom M King]

Google "adjusting coil on honda mower motor" , and you will find videos on fixing any of the few possible problems.

[Jed Hefley]

I had a small motor lose spark once. Ended up being the low oil safety switch. Somehow it went bad, and interrupted the start circuit. Checked oil, unplugged switch, and it started right up. I’ve also had the flywheel misalignment deal happen, but that was after I ran over a buried steel pipe and stopped the mower dead in its tracks.

[Morey St. Denis]

In my experience, you can readily remove the flywheel retaining nut at the top of the crankshaft. Should be able to visualize those keyway grooves enough to judge if the flywheel key might be damaged without needing to actually pull the flywheel. Regardless, I happen to have the Honda of America authorized lawn mower Shop Manual at hand and it does show an ignition fault tree diagnostic guide that has specific recommendations regarding this problem.

In the instance of testing for spark and observing none, it states: "check with a new spark plug", "check again with a new spark plug cap" (might also just verify good continuity with a meter if available), "locate the engine electrical stop switch & disconnect the black wire that grounds out spark, then recheck"; in that order.

If after completing these procedures, there is still failure to detect any spark, we've arrived at: "Defective transistorized ignition coil" & "Replace transistorized ignition coil". My manual covers Honda models HR195, HR215 & HRA215 in particular and is dated, 1995 thru 2011. Might give these suggestions a try and pay particular attention to verifying good continuity in those conductive elements (clean plug, wire & plug cap) also don't forget about that electrical ground kill switch at the bottom end of the throttle linkage. Could simply be a bad stop switch mechanism shorting your coil-induced spark potential to ground.

[Lee Schierer]

Most likely your mower has several safety interlock switches, Before taking the motor apart, I would check the switches for continuity.

[Larry Frank]

+1 on checking the safety switches and plugs. I had that happen last year.

[John C Cox]

Most likely your mower has several safety interlock switches, Before taking the motor apart, I would check the switches for continuity.

BANG!!! X 1,000,000.

Check all the safety switches and their associated wiring first - especially the deadman handle grip switch. If it has a low oil switch - check it too.. There are probably safety switches on the self-propelled drive engagement and blade engagement if it had any of these - they prevent you from trying to start the motor while the blades are engaged or the drive is engaged.......

These switches generally all work by grounding out the coil... So you get no spark.

As another dumb item - make sure the spark plug wire isn't grounding out via damaged insulation on the wire... That one has gotten me many times..

[Bill Dufour]

OP here: ended up the coil was bad. Measured no short to case or anything bad. Probably from rain water running down the cable to the inside. New coil was about $10.
Lots of kits on ebay that include a new plug, coil, and the complete starter rope housing assembly. that and the car are about all that could cause no start condition. Those kits cost around $25.
Bill d

[Tom M King]

Did the coil come with something to set the gap by? Have it back running?

[Bill Dufour]

Back and running. I set the gap with two twenty dollar bills. The recommended gap is a business card which I did not have in my wallet.
Bill D

[Jim Koepke]

Back and running. I set the gap with two twenty dollar bills. The recommended gap is a business card which I did not have in my wallet.
Bill D

Reminds me of the days when people set their point gap with a match book cover.

jtk

[Morey St. Denis]

Bill, you never did mention what model or decade of Honda mower you're working with, nor its self propelled transmission type... Plastic deck or cast aluminum?

[Robert Engel]

Mustie1 on YouTube.

You'll learn everything you ever wanted to know about getting an engine going. :-)

[Bruce Wrenn]

Back and running. I set the gap with two twenty dollar bills.
Bill DBig spender, I would have used a couple of ones instead. Glad to hear everything turned out well. There is a satisfaction from fixing something, that just can't be explained.