# Craftsman 536.881750 7.5 HP B&S stalls after 15 mins of use



## Snowman91 (Feb 3, 2015)

Hi everyone I am new to this forum. I am hoping you can help me with my Craftsman snow blower. I owned it for over 10 years but did not use it too much.

Currently the snow blower would work for 15 mins good and start to stall and run rough. The snow blower will stall especially when i hit the auger to shoot snow even without snow. After the blower stalls it is very hard to restart and even if it does it will stall shortly after.

I have already replaced a new carburetor and spark plug. I emptied out the gas and used fresh sunnco 93 octane gas. Can someone please help me out. Thank you in advance.

I am also curious to know what provides spark to the spark plug. I was thinking the coil pack might be broken but I cannot find that part online.


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## Tom5407 (Jan 19, 2015)

I believe you have a briggs and stratton engine and need to id it first then look up engine parts like the ignition. This should help How do I identify a Briggs and Stratton engine


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## Motor City (Jan 6, 2014)

Next time loosen the gas cap to verify that the vent on the cap isn't plugged up. It will starve the engine of gas. If that isn't your problem Check for spark after it quits. The coil could go open after its heated up.


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## conwaylake (Feb 6, 2014)

*Classic Carburetor Icing ?*

Please check out my post #20 in this thread: 
http://www.snowblowerforum.com/forum/craftsman-snowblowers/13225-stalls-when-wet.html 

Which describes Briggs & Stratton 590907 Carburetor (kit) . 
Make sure that your 'replacement' carburetor looks like the photo. 
I have a 8.5HP B&S, my neighbor has a 6.5HP, both are vintage 2005 machines, and take the same carb kit. 

The full model number for my 8.5HP motor is 15A114-0342-E1 . 

Your symptoms indicate that the motor is fuel starved. I claim that the cause is *carburetor icing*: moisture in the air condenses on the sides the carb throat: the high-moving, low-pressure air is COOLED, and the water vapor in the air stream condenses out at the cooler/lower pressure carb throat, onto the cool sides of the carb, building up, and eventually restricting the passageway to mimic a 'fully-choked' engine. 
PLease take note of the non-metallic spacer between the carb and the block, which would insulate the carb from motor heat. There are also theories of 'vapor lock' , which I think are bogus. 

If you do suspect the coil, then the next time it stalls , immediately pull the spark plug (may require pulling off a cover or two), and check for spark against bare metal on the motor, or get a cheap spark tester from AutoZone, NAPA, etc. If you still get a strong spark, then your problem is not the coil. (Of course be sure you have the correct spark-plug installed).

I've done a lot of googling on the subject. One early poster to this forum fixed the problem by simply blocking the vent holes on the recoil starter shroud. He claimed it kept the snow/mist from getting into the carb. 
BUT I also found a noticed from John Deere, instructing their shops to cover over the starter/flywheel vent (same thing). *TO MAKE THE MOTOR RUN WARMER, to counteract carb icing *!!! OMG !!! 
Granted, there is some risk to running the motor hotter, so you might want to avoid this 'fix' on a 40 degF sunny day in early spring. 

My neighbor has not yet upgraded with the new carb kit. His solution is to 
run a hair-dryer onto the motor, 'carefully' under a tarp, for about 1/2 hour. 

Replacing the coil is 'simple', but requires removing several cover pieces. 

Your motor is 12C113-0251-E1 the original part # for the coil was 697929 ("Armature-Magneto"). The current replacement part is *796964 * ($41 from Jacks Small Engines)

I got that same coil, (Briggs and Stratton 796964, from Amazon $30) but have not replaced it. I'm not convinced I have a coil issue.
General research indicates to me that the carb issues dominate the possibility of failed coil. Here is a video on replacing the coil, from Appliance Parts, Lawn Mower Parts, Heating & Cooling Parts. 365 day returns.. It's not on a snowblower, but the only difference is the air-filter/Snow-hood.:


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## Snowman91 (Feb 3, 2015)

After changing coil ive noticed the engine running a lot louder. The exhaust gets glowing red hot and i see flames coming out like it's backfiring. Any idea what I might of done wrong to cause this? I still used the snow blower and it no longer stalls but now I have this new issue.


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## Toro-8-2-4 (Dec 28, 2013)

The louder sound could be that you got use to it running with a poor spark and now the spark is strong with the new coil. Also, Your muffler baffle may have corroded away.

A red hot muffler could be any one of or a combination of:

1. Running too lean. check and adjust if adjustable and or clean carb. Check for air leaks in the intake and carb gaskets.
2. Exhaust valve is not closing. Check valve clearances.
3. Running too high of an octane. Higher octane burns slower and since you can't advance the timing on a small engine it may still be burning on the exhaust stroke.
Ditch the Sunoco 93 octane for 87.

I hope this helps.


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