# No spark - any other thoughts?



## HCBPH (Mar 8, 2011)

Bought a blower last year with the intention of refurbing and selling. It has a Tecumseh HM80 engine (points and condensor). Had some issues but I did see it run that day for about 20 seconds.

Fast forward many months and started fixing the issues: broken starter, buggered up starter ring on the flywheel, gummed up carb etc. I tried to rope start it and got it running once for maybe a minute and ran like crap. Not able to start it again.

I've swapped my flywheel for another identical one (same part number etc from another HM80), fixed the stripped starter mount hole and picked up another starter. It has a new carb (though I did try the old one), new sparkplug gapped to 30 thousands, new points and condensor gapped to 20 thousands. I have no spark what-so-ever. Unfortunately I did not confirm whether spark was present before I horse traded the bad flywheel for the one with the good starter ring. I have confirmed it's the same flywheel though by visual, part number and measurements.

I've checked using both a inline spark checker (plugs between the plug wire and the plug) along with grounding a plug on the head and watching the plug gap for spark while spinning the engine with the electric starter. I have no spark at all.

I've triple checked the flywheel, it has the same part numbers cast into it, both magnets are there in the original position and doing the screwdriver test from the Tecumseh manual, they look good. No magnet damage, original position and compared my measurements from the old one are in the exact same position. They flywheel to crankshaft key is present, so the timing on the flywheel to magneto should be correct.

Points are opening and closing as they should - tested with an ohm meter both the orignal points and the replacement. It tests OK to block (not shorting out to ground).
The grounding wire is removed for now so it's not grounding by accident.
Unhooked the magneto coil from the points and ground, checking the wire that hooks to the points through the wire that grounds out under the condensor mount, shows continuity throughout the wiring and does not ground to the block.
Plug wire connector where it connects to the sparkplug clips on solid.

Everything seems good to me, about the only thing I have not found a way to test is the actual plugwire that goes from the magneto coil to the sparkplug.

Anyone know of any way to test the magneto coil off a unassembled motor? Or know of any other tests that can be done at home on the magneto to confirm whether it's good or not? I can't think of anything else that might be causing the no-spark issue as everything else checks or has been replaced.
I don't want to throw any more parts at this thing without knowing it's the problem.
I've double, triple and even quadruple checked things without success and I've run out of ideas other than maybe the magneto coil.

Thanks in advance for any ideas.

Paul


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## Colored Eggs (Dec 7, 2012)

The Kill switch is working correct? I just googled some stuff and all I have found is for cars and they were disconnected from the coil.


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## bwdbrn1 (Nov 24, 2010)

Borrowed this from justanswer.com.

With coil not hooked up take an ohm meter and put one probe on the end where connects to spark plug. Then put other probe on coil metal base. The reading should be between 2500 to 5000 ohms. If you are getting any other reading coil is shorted out and will need to be replaced. Even though points look good they can still be bad. Try filing the points or emery cloth on them. Don't forget to reset the point gap after you clean the points. Set at .020 . If you need further help just reply back.

Read more: how do i test the ignition coil on tecumseh engine model h - JustAnswer how do i test the ignition coil on tecumseh engine model h - JustAnswer


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## HCBPH (Mar 8, 2011)

*Got spark*

Believe it or not, got spark now and you won't believe how.

Took it all back apart and put it back together, no change. Well it happens I have a couple of motors on my blowers that are close enough to be temporary donors of parts. My plan was to swap one part at a time till either I had it fixed or ran out of things to swap.

Started with the simplest thing and planned to work through everything if need be so I started with the sparkplug. I've got spark. Put the original back in, no spark. Put the one I had just bought Thursday, no spark. Put the one from my other blower in and I've got spark.

Apparently a spark tester fails if you have a bad plug, and when the replacement plug is bad you're still in the same boat.

Well it's looking alot better. The only other thing might have been threatening it. I let it know I had a boxed clone engine in the corner and if it wasn't going to work then the clone would go on the blower. One or the other worked. 

I guess it comes down to whether new or used doesn't guarantee a part is good until it's tested out.


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## Colored Eggs (Dec 7, 2012)

Glad you were able to figure it out. Was there a difference in the gap or was the new spark plug just defective.


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## HCBPH (Mar 8, 2011)

*Plugs*

Sure looks like both the plug that had been in the engine along with a brand new one were bad. I planned to start with parts I knew worked, that being parts from an engine that started and ran.

Just for giggles, when I have a little time I plan to put that newly purchased plug into the source engine and see if it fails there. I don't know why it would fail in one engine and work in another but I suppose anything is possible.

Regardless, at least I have spark now so I can continue with reassembling it. Don't know if it was stated, when the spark was failing I had removed all the things like grounding switches etc, it was just the stuff required to generate a spark.

Next phase is to finish putting it all back together and see if it actually runs.


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## td5771 (Feb 21, 2011)

just an fyi, bought brand new tecumseh point set and put it in a 6 hp tec. everything set perfect and there you go right?...no spark

as it turns out where the stud goes through the insulator it was a bit lower and the points spring when put in properly was touching the mounting plate for the points grounding it out causing no spark.

solved that issue then.......still no spark

a little cursing and further examination.

The flat steel spring that holds the arm/points against the crank eccentric did not have the same bend so when i set the points at .020 at wide open they stayed there through the whole revolution of the crank....they never moved. re-bent the spring and now we have life.

man what a fiasco.


just something to stick in the memory


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## HCBPH (Mar 8, 2011)

Well the points and condensor set I bought were labeled "Made in Argentina". Like Ive said, it's impossible to keep a Made in the USA engine 100% American if you can't also find US parts.

I've got a clone engine I bought for a blower likely needing an engine. I opened the box last night to give it a quick once over and quite frankly I find it hard to believe it will still be running 40 years from now like some of the Tecumseh's have to date.


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