Italian Mister

lefty2cox

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Efco AT 9500
Back Pack Mister
EXH/EVG Family KE8XS 0775CF (Not sure if this is helpful)
Serial: 54894800121119
Another number on the machine is: 9999450128
76.5cc

This runs well 90% of the time. The owner reports this procedure:
Prime, choke, pull twice and it starts for a second then stops. Choke off, pull and he's off to the races.
Occasionally, it's prime, choke, pull twice, start for a second, choke off but then nothing. It won't start no matter what he does at that point.
The last time he brought it to me, I was unable to replicate. It started and ran fine for me every time.
Came back again after the same symptoms and I'm now experiencing the same thing.

The compression is 120. No carbon buildup. It just pretty much floods. The plug comes out wet.
This machine is less than a few months old. He purchased new and uses it commercially. Not sure where to start. I inspected the cylinder through the exhaust and with a scope. Everything looks ok.
I checked the spark and it looks pretty weak to me. Almost intermittent. But I'm not sure what it's supposed to look like. Is that a common failure on something so new? Every time I go chasing spark on one of these 2 strokes I'm talked out of it. Plus, it's almost brand new. But it certainly feels like a spark issue to me. But I'm no pro. Any guidance is appreciated.
 

ILENGINE

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It could be a spark issue, but also could be a carb issue dumping fuel into the intake because the carb is leaking internally. Replaced a carb on a Makita a couple a month ago because of the same issue. You could remove the plug and turn it upside down and drain the fuel out of the cylinder and crankcase.
 

lefty2cox

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I'll give it a try today and report back. Thank you.
 

lefty2cox

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No luck. I think I'm going to try a new plug and then tackle the carb. I can't image it's bad diaphragms being so new. Maybe something keeping the needle from seating?
 

lefty2cox

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I have some info regarding a new plug. I picked one up and gapped it to spec. I first tried it without gapping and still no start. I then gapped it to .5mm, which is the spec. Now I can get it to start and sputter but haven't been able to keep it running. I'm pondering what that means. A big difference between the two plugs, one running kind of and the other not starting at all.

For what this is worth, there is a difference in resistance between the old and new plug. The old plug was showing 11k ohms and the new plug is 25k-ish. Keeping in mind that Ilengine's theory of too much fuel is still a possibility, does this new info shed any light?

Thanks
 
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