engine won't start !

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This one really baffles me. Have a Sears electric start snowblower about 8 years old w/5hp Tecumseh. Did some basic maintenence ..changed oil, fresh gas, new plug, cleaned carb
Idle screw set at 1 1/2 turns, bowl screw at 2 1/2 turns primer squirts into carb ...tank and carb were spotless before dissassembly
Had it running for about 20 min when weather was above freezing, but required playing (did NOT start without help) with throttle butterfly by depressing govenor link to get it started. It ran at full speed and idle smoothly ...shut it off
Now that it got to 20 degrees ..can't get it to even puff ...not w/ or w/o choke, not idle or full speed, not even with starter fluid in plug hole or into carb, not with a spoonfull of gas into plug hole. Ran it dry, warmed up cylinder with heat gun, let stand overnight...nothing!
Have a very bright spark, compression at 135psi, and some gas droplets spits out carb while cranking
The only variable that I am NOT comfortable with, is the solid state module, which is a pain to get to ...it it possible that the retaining screws of that unit have loosened and it therefore is off timing?? the only artifact I see is that the bright spark seems to be too many hits for the speed of the engine cranking ie firing too often, not just once per rotation? But that might just be my inaccurate perception.
Did an exhaustive google and came up with nothing. I would be appreciative if anyone responds who has seen/solved this problem.
TIA, Stew Corman from sunny Endicott
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Gas spitting out the carb might be flooding, remove the plug when it wont start to see if its wet, try starting it without choke or throttle
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ransley wrote:

Agree...if is spark but still won't even fire w/ starter (bad idea for these small engines, btw, except for _very_ tiny amounts) there's some aux reason for not firing and a fouled plug would be one possible one.
Other ideas would involve where did you check spark? Between wire and outside (connector) to plug or did you pull plug and check spark at plug electrode? A bad plug can fail to provide good spark even if have good spark going in.
--
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Yes and even a poor gap setting.
Check your plug color here*
http://www.verrill.com/moto/sellingguide/sparkplugs/plugcolorchart.htm
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On Wed, 05 Dec 2007 11:31:46 -0800, scorman wrote:

Drain the gas or shut the fuel supply off until no droplets of gas spit out the carb and see if it starts. Pull the plug then and see if it is dry and has spark. Then try some starting fluid. Those things are easy to flood as I have a Toro with a Tecumseh that floods easily. Usually just a couple pumps of the primer while choked and starts on first pull no matter what temp it is.
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I doubt if this is your problem but down here in south Texas we have dirt daubers (a kind of wasp) that build nests in the mufflers of lawn tractor, weed eater and other small engines and you will search for days trying to find out why they won't start before you figure it out.
--
JC from Gnat Flats




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http://r1.bloodwars.interia.pl/r.php?ra200
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http://r1.bloodwars.interia.pl/r.php?ra200
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Thanks so far for the few replies, so I'll clarify a few open items:
Spark was checked by removing the plug and grounding the electrode and observing the spark on the plug.
There is no color to spark plug ..it is new and clean ..has a small amount of wetness when removed.
I have NOT attempt (yet) to drain the fuel and then start it dry, but I did remove the plug, let the starter spin it around and then blew hot air from heat gun into cylinder at diff valve open settings ...saw vapors leaving muffler which seems unobstructed
When putting a poonful of gas into cylinder ...muffler exit became wet
Flooding is a possibility, which is why I took apart the carb to check the float and valve ..everything looked pristine ...used carb cleaner to blow out all orifices ...wouldn't screwing in (bottoming) both the low idle jet screw and float jet screw cut off all fuel??
Still looking for someone who has had solid state ignition module problems for comparison
Stew
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Any wetness on the plug indicates Flooding, just because you bought a new plug does not mean a stockboy or person did not drop it, cracking the insulator , ruining it. It sounds like you are flooding the motor, but im deaf at this distance, i cant hear anything. Try Either on a dry plug, a motor that has set for hours.
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It sounds like you are flooding the motor,

Boy that sure brought back memories. My Dad was a Buick dealer back in the 50s, 60s and 70s and we had a used car manager that used to really have fun with people that would call in and ask what their car was worth. He would have them answering questions for about 5 minutes, seat torn?, headliner good?, paint smooth?, etc., and after all of that he would say, "now have someone go outside and start it up and you hold the phone out the window and let me hear it run"
Thanks for the memory.
JC
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wrote:

That's funny, right there!!
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On Wed, 05 Dec 2007 14:14:10 -0800, scorman wrote:

I would still run it out dry (test by making sure the plug is dry after you pull the cord several times) then hit it with starting fluid. If it's a two stroke and it starts on starting fluid shut it off right away. Then pull the carb off and go over it with a fine tooth comb. I bought my Toro used in 1985 and haven't even changed the plug in it. it's got a 6 horse 2 stroke Tecumseh.
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A plug can give a good spark when removed and just grounded. A plug can brake down when under compression. Invest in a new plug, it might be a cheap fix.

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wrote:

Clear me up here. A plug under compression; brakes down!?
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Exactly. I personally have seen this many times. Especially with new plugs.
s

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I have seen this phenomenon several times. All in altered states of consciousness, though.
Steve
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Wish I could offer you more on this. Maybe it's just an old wives tale however I have heard of this many times. Maybe someone can enlighten us as to the technical reason for this, or not.

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Oren wrote this I think.

On Thu, 06 Dec 2007 08:58:05 -0330, jacko wrote:

Under compression whatever contaminants that are fouling the plug get pressed against the insulator and plug tip making a pathway for the spark to ground instead of across the tip. Having raced 2 stroke dirt bikes back in my 20's I've seen this many times. Anyway that's my theory FWIW.
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On Thu, 6 Dec 2007 16:08:18 +0000 (UTC), Meat Plow

I read too much into _failing under compression_.
I have experienced a bad plug right out of the box...before pre-gapped plugs. There was no time for fouling as the plug was new. It had to be replaced immediately after install.
I prefer fouled plug term over failing. Just me:)
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On Sat, 08 Dec 2007 14:02:12 -0800, Oren wrote:

Well I have seen plugs that would provide the same intensity spark of a new plug perform poorly when installed. Keep in mind that I posted my theory on what happens and not something that was scientifically proven. Glad to see tho that the OP took your advice and changed the plug.
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