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b&s 8.5 hp motor on craftsman snow thrower


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12-22-11, 06:30 AM   #1  
b&s 8.5 hp motor on craftsman snow thrower

I cleaned carb,fuel system, I have spark, i get gas on prime,..still wont start...(this was original sympton,as well}...pull cord several times..get a fart..which gets louder the more i prime...I HAve compression on my thumb of some sort....I think ..ohv adj..? timing prob..?...also my friend may have changed plug....reg y19 ...or does it need resistor plug..???? PLEASE GIVE ME SOME ADVISE,,,THANKS

 
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12-22-11, 07:02 AM   #2  
Which engine do you have? The model number should be stamped on it somewhere. We can't give any specific help until we know what engine you have.

Try removing the spark plug and pour 1 teaspoon of gas into the cylinder. Re-install the spark plug and give it several pulls. Does it sputter or try to fire better than it did before adding the gas? If yes then I'd look at the carb. as the source of the problem. Even if you cleaned it there still may be something clogged, improperly set jet or worn out, broken or missing parts.

 
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12-22-11, 10:46 AM   #3  
The model # is 15a114 0342

 
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12-22-11, 11:27 PM   #4  
No tried tsp of gas after severel pulls it poped.....tried some start fluid,,,,riped cord 1 time....major backfire,,,2nd,iiii I GOT INTERNAL PROB..

 
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12-23-11, 05:12 AM   #5  
Do you know if the engine had a sudden stoppage? Running full throttle blowing snow and maybe catch a big rock that stops the engine dead in it's tracks? If so it's possible that the flywheel key is sheered which can get the timing off. In some rare cases (on racing engines) I've seen a back fire strong enough to sheer the key. Remove the flywheel and look at the key that goes between the flywheel and crank shaft. It should be nice and square. If it's broken into two pieces or has a bit of a "Z" profile it needs replacing.

Another easy thing to do is remove the cylinder head. Then slowly pull the starter cord and watch the movement of the piston and valves. You should insure that everything is moving in the proper sequence for the intake, compression and exhaust strokes.

 
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12-23-11, 06:37 AM   #6  
This will be an overhead valve engine and the head removal should not be necessary. But! I'll bet you have a valve out of clearance...remove the rocker cover and measure each valve's clearance. Set both at .005".

 
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12-23-11, 02:10 PM   #7  
Doh! I even looked at the engine diagram and still had it stuck in my head it was a old side valve.

When you have the valve cover off, remove the spark plug and slowly pull the starter cord. You should see the valves moving hopefully indicating that one is not stuck.

 
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12-28-11, 05:26 PM   #8  
8.5 b&s

SORRY ITS BEEN A WHILE,,,iI LOOKED AT OH VALVE OPPERATIONS LOOKS O.K. TO ME ....OWNER TOLD ME A NEWS PAPER GOT STUCK IN IT......(THE AUGER)...SINCE THEN IT WOULD RUN 5-10 MINUTES...THEN DIE...UNTIL AFTER SOME TIME IT WOULDNN'T START AT ALL.....LOOKING AT PARTS DIAGRAHM ON THE B&S ..IT SHOWS A TIMING GEAR WITH A KEY INSIDE BUT HAVE TO OPEN MOTER TO CHECK.....ITS ON OPPISITE SIDE OF FLY WHEEL SIDE OF THE CRANK SHAFT...NEED GASKET SET..??? ANY OTHER WAY TO CHECK,,,,,UNLESS IM READING DIAGRAHM WRONGGG....PLEASE ADVISE..
\

 
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12-28-11, 06:06 PM   #9  
The flywheel key is not inside the engine. You're looking at the crankshaft gear key on the diagram. Look at the big round metal wheel at the front of the engine under the pull rope... this is the flywheel. It has a key that shears. Most likely this is your problem. You don't have to take the engine apart to fix it.


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12-28-11, 07:21 PM   #10  
8.5 b&s

Iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiichecked it....

 
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12-30-11, 08:55 AM   #11  
they are gaped between .005 & .010 .........................................................................

 
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12-30-11, 02:44 PM   #12  
Thanks.................that was it...I was going there first before, taking motor apart

 
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12-31-11, 05:28 AM   #13  
What, was it? The key or the clearances...because .010" is way too much for an overhead valve engine.

 
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