4.5h.p. mtd snowblower spits gas out carb.

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  #1  
Old 09-01-08, 10:53 AM
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4.5h.p. mtd snowblower spits gas out carb.

Hello, I have an MTD snowblower with 4.5 tecumseh. When I pull the starter rope it spits the gas out of carb. I have cleaned the carb, bowl etc,. Have checked compression, spark and even switched carb with another but still get same thing. Any thoughts? or hints? Thanks
 
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Old 09-01-08, 08:05 PM
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Is this a 2 stroke or a 4 stroke? What kind of compression numbers did you get? How old or how much use?

It could be intake valve not seating properly, exhuast valve stuck closed. Cam jumped time.

I would check the valves and the valve stem clearence.

Good luck - let us know what you find.
 
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Old 09-02-08, 10:49 AM
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Check the flywheel key. Sounds like it is most likely partly broken, throwing off the timing.
 
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Old 09-03-08, 01:52 PM
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Checked flywheel key its fine. I was actually hoping that was the problem, would be easy fix. Thanks
 
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Old 09-03-08, 01:56 PM
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It is a 2 cycle. Only 2 seasons old. Lady I bought it from said it was running fine one day, wouldn't start the next. Looks like I'll be checking valves next. Thanks
 
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Old 09-03-08, 02:45 PM
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Please post the model numbers for the engine so we know what you have.
If it's a 2-cycle there are no valves to check. If you didn't remove the flywheel to check the key I would suggest removing the flywheel and checking the key. Have a good one. Geo
 
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Old 09-05-08, 04:42 PM
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Hsk 845 8222d. went to partstree.com, saw the parts list and see what you mean about no valves. Flywheel key is 100% intact, timing can't be off?? Still don't get why it pushes gas out of carb instead of drawing it in when rope is pulled.
 
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Old 09-05-08, 07:22 PM
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Well the next thing I would check is the exhaust. Could have something in the exhaust of the muffler, or maybe the port itself has carbon buildup.
 
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Old 09-08-08, 04:18 PM
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Nothing plugging muffler or exaust port.
 
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Old 09-08-08, 04:39 PM
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Well if the muffler and exhaust ports are clear, there must be something going on with the piston, cylinder or ports allowing pressure to feed back through the intake, although a small amount of "spit back" is normal on most 2 cycle engines.
 
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Old 09-13-08, 05:13 PM
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I did a compression check, the gauge read 29. I am getting alot of spray back, almost as if the exaust and intake stroke were reversed. Checked flywheel key, changed carb even took the piston out, everything looks fine no excessive wear or any obvious problem. This one is driving me nuts. Ready to buy a used engine off of ebay, but that would mean this one has beat me and I refuse to be beaten! Any other thoughts you all have would be much appreciated. Thanks for all the help and suggestions so far. I'm really glad I found this site.
 
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Old 09-13-08, 07:59 PM
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I'm not familiar with the engine, is it piston ported or does it have reed valves? 29psi is waaay too low.
 
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