# Yet another Tecumseh HS50 that won't start



## ofranzen (Jan 8, 2006)

*Yet another Tecumseh HS50 that won't start - SUCCESS!*

Hi all,

First post here and I am hoping you can help me out. I started this thread over at another forum but I haven't gotten any more replies in a couple of days. Hopefully you are more active over here. I apologise in advance for a lenghty post, but it is a lenghty problem  Also, please correct me if I get the terminology wrong. I'm from Sweden and not used to discuss engine specifics in English.

So, to summarize that thread and my problems:

This HS50 is mounted on an Ariens ST504 snow-blower.
Up to last week, it used to start on the first try. Throttle on 50%, full choke and three pushes on the primer and it would start
There's fresh petrol in the tank
I've opened the carburetor and it looks clean and the float seems fine. Maybe I dislodged a stuck float because after I put the carburetor back together I was able to start the engine and have it running on an unsteady idle for a minute before it died. Any attempt at raising the throttle would kill the engine.
Now, after haveing done noting since the condition in the above bullet, it's impossible to start the engine. No spark or nothing and that's where stuck.
I've tried to get my head around the ignition system on this engine but everything is so hidden. I checked the spark with one of those test lamps that you put between the spark plug and the spark plug wire and at the beginning of my attempts, I got a clear spark. Now the test lamp has broken for some odd reason and I can see no spark if I take the spark plug out and ground the tip to the engine block.

A few specific questions at this point

Should I be able to see a spark when grounding the tip of the spark plug and pull the start cord? Or is the spark so much fainter that on a car that it won't be visible?
The black wire that comes out from under the pull-start cover and that connects to the black lead to the ignition switch is always grounded. Should it really be like that? I thought setting the ignition to "off" grounded that wire by connecting it to ground via the red lead from the ignition switch. I.e. ignition off = black wire from under the cover, via the black wire to the ignition and then to ground via the red wire. Turning the key breaks the grounding via the red wire and the engine can start. Am I wrong here?

Thank you in advance

/Ola
Sweden


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## rake60 (Oct 13, 2005)

Your engine may have a points set and condenser. 
You might try replacing and set them as specified in the service manual.

Rick


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## ofranzen (Jan 8, 2006)

As everything is so compact and hidden on this engine, this is what I have found so far. The gap as indicated in the bottom illustration on page 70 (74/123 in the pdf page counter) in this manual http://www.cpdonline.com/692509.pdf is too big on my engine. It should be 0,0125"/0,3175mm but mine is over 0,02"/0,5mm. 

I'm gussing this is way too much and that's why I don't get a spark. Right? How do I adjust this? Do I have to remove the flywheel or can I get to the adjustment screws through the small inspection hatch just by the laminations/magnets? I could messure the gap through this inspection hatch but am not sure if I can adjust it too.

How can the engine have been running just fine with this gap and the suddenly given up completly?


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## ofranzen (Jan 8, 2006)

Having gotten some further info on another site I have gathered that the wire I mentioned coming out from the flywheel shroud and that goes to the ignition switch should *not* be grounded at all times and that it's the reason for me not getting any spark. If I disconnect the wire from the ignition switch, it is still grounded at all times.

Any ideas on typical spots to check for corrosion or other problems? The ignition system is terribly well hidden but I'm guessing that taking the entire engine apart is the next step in getting this running.


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## rake60 (Oct 13, 2005)

Ola
The wire coming out from under the blower housing is a kill wire. If it's grounded you will not have spark. Trace that wire back to the coil and try disconnecting it there. It should be plugged onto a spade connection. If the spade connection on the coil tests a dead short, the coil may be no good.


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## ofranzen (Jan 8, 2006)

Is anyone here familiar with this particular engine and can tell me if I need to remove the flywheel to get to the coil? It seems like it but maybe there's a moer clever way to do it.


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## bugman (Aug 12, 2004)

if the coils under the flywheel, the flywheel has to come off to check it.


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## albert (Jan 15, 2006)

Pull the coil & check for continuity.Also,pull the fly wheel to see if the keeper(the piece of key stock that holds the fly wheel to the shaft) is broken or chipped. It'a pain ,but by replacing it it will help


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## ofranzen (Jan 8, 2006)

I finally found the problem!

I took the flywheel off and checked the point gap, condeser, coil continunity and that there were no shorts and I could not find anything wrong. Then as I was sitting there looking at the crankshaft and the flywheel and remembered what albert wrote and realized that the key that keeps the flywheel and crankshaft in place and saw that it was sheared in two...

That's why I could get it running for a while on idle - the timing was just a bit off then. Then I got no spark at all - because with all the start attempts I had moved the igniton timing too much off and got no spark at all.

So, I took the larger of the pieces and jammed it to hold the flywheel in place temporarily and now I got a spark.

Finally...

Now I just have to get a new flywheel key. Thanks for all your help.

/Ola


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## bugman (Aug 12, 2004)

any small engine shop should get you some, they're pretty cheap. was anything hit, or it stopped ubruptly? that usually shears the flywheel key.


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## ofranzen (Jan 8, 2006)

The neighbor ran the snow thrower the last time before it broke so I don't know. They said that they didn't notice anything strange when they ran it but maybe all the pullstarts sheared the key.

Getting a new flywheel key shouldn't be a problem and thanks again for all your tips. I might return for some tips on carburetor adjustments though)

(Ola


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## ofranzen (Jan 8, 2006)

*Oh for Pete's sake!*

Now what...? I swear this engine is out to break my spirit...

I got the flywheel key and installed it. Checked and cleaned the magnets and coil core and checked the gap. Checked coil continuity, capacitor, cleaned the points and checked the gap. I could easily get a spark just by turning the flywheel by hand so I assembeled the engine to try it out. After assembly I checked if I still had a spark and sure, nice and strong and the kill switch worked.

So, I primed the engine and pulled the starter a couple of times. Third try or so I got a cough and then nothing. Checked for spark. Nothing. Changed spark plug and checked the gap. Nothing...

So now I have to take everything apart again and I'm *really* close to just tossing the darn thing into the pond....

Why did I loose the spark? What should I check?

Please help me again.

/Ola


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## jamesinhulsen (Feb 3, 2006)

I had an old engine, and bought a "solid state" electronic ignition kit and it starts every time now. check out mfgsupply.com, jackssmallengines.com, awarehousing.com

I was able to leave the old parts that didn't need touching in place and just add the new with detailed instructions. 

good luck


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## bugman (Aug 12, 2004)

must've missed this one..... but yes a ignition conversion kit woulf get rid of the points and condensor, but also, the flywheel key, key slot was clean and free of any dirt, rust or oil, and was tightened to spec? if the nut was put on there loose, it'll shear the key


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## ofranzen (Jan 8, 2006)

I started a new thread here and got it working. This thread can be considered closed and thanks again to all you who helped.

/Ola


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