# Craftsman 536.881851 surging



## loridinnx2000

Hello, just about at wits end on this machine. As above its a 536.881851 with a briggs 8.5 with 27" path. I can put the choke on hit the primer 2x and it will start right up put the choke half way it runs nice and smooth shut the choke off and idles up and down rough I have rebuilt the carb many times,cleaned the tank,blew out the fuel lines nothing has changed. I have searched on here about the other problems stalling out which usually involve blowing snow and carb getting wet. However mine can be in the garage take it outside fire it up let it idle in the driveway it will start reving up and down then stall. I have tried this with the gas cap tight and loose still no change. 

Has anyone pulled the screen out of the tank and added a small inline filter instead?


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## conwaylake

*did you replace or just rebuild the carb?*

I've also read on this forum that rebuilding/cleaning a carb can be tough when it comes to getting all of the passageways clear, replacing the Welch plug etc. 

This replacement kit ( Briggs & Stratton 590907) costs like $50 .
I have heard that it has slightly larger bowl on the carb, which seems to point to a remedy to the fuel-starvation problem that you describe. 
It fixed my icing problem, but also runs great in dry conditions. 

Your problem indicates that the idle circuits are failing to keep up with the demand of regular idle. You are not running fast enough (or under load) such that there is vacuum to draw fuel through the main jet. 

So the carb upgrade kit might address two issues: 'non-perfect' rebuild, and bad design of the carb.


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## Kiss4aFrog

Installing a fuel filter is always a good idea. I prefer to use something clear so I can see what's in there for dirt and or water. Lots of choices on line or at an auto parts store, big box store, hardware store and Walmart.

If your engine is "hunting" but smooths out with the choke partially applied then you are running lean and you need to do a better job cleaning the carb or replace it to cure the problem.
You might want to review a video or two on youtube to make sure you're getting it all clean. Like Conwaylake said it might just be one circuit you missed in that carb that's causing you the problem 

https://www.google.com/#q=donyboy73+tecumseh+carburetor


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## Hankfard

Also don't forget to use fresh new gas; nothing sitting longer than 60 days, whether "stabilized" or not. Definitely get new gas if it is smelling the least bit like varnish. 
Don't put too much faith in stabilizers, as they cannot restore gas to its as-new volatility and octane rating. Using old gas is VERY often overlooked as a potential cause of starting and running problems. 
If your gas tank is metal, you can add fuel system rust to the list of potentially contributing issues. 
BECAUSE: The longer fuel sits in any tank with periodic contact to open atmosphere, the more water it will absorb because of the ethanol content.


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## thombat4

*What I did to fix mine...*

Hello all,

I too am the proud owner of a 536.881851 Craftsman Snow Thrower and it too displayed all of the symptoms described here. I got mine via craigslist and it looked as if it was brand new. Fella I got it from said it was his dad's and it sat in a barn for a couple years. Well after I got her home and gave it the once over which involved taking all the covers off and cleaning out very packed in mice nests throughout the machine, I plugged it in (because the pull start was jammed) and tried starting her up. It started right up just fine and shortly afterward began showing signs of dying out. I cleaned the carb and no change. I replaced the whole carb and made the appropriate changes regarding the governor. Still no change in the behavior which while frustrating as it was it pointed me in another direction. I figured if the issue was not fuel related then it must be electrical. I considered replacing the plug but the machine would fire up every time with 2 pushes of the primer. So i did some more research and decided to look into replacing the ignition coil. I'd never done it before but I have all the right tools and dug right in. I found a $20 coil on ebay with free shipping at New Briggs Stratton Electronic Ignition Coil Fits 695711 802574 796964 | eBay

Installation involved removing the 3 bolts that hold the pull starter in place and removing the 2 screws that hold the gear selector bracket. Removing the gear bracket allows you to remove the pull starter assembly. The coil is readily visible and easily removed by 2 screws. Detach the other end from the spark plug and remove the boot and pull the whole assembly free. Upon visual inspection a few of the fins were not making contact with the rest of them like they should be. Whether or not that's what the issue was I'm not 100% sure. Nevertheless when the new coil was in place and everything put back together it ran like a fat boy to the kitchen!!! This machine is now the beast it was meant to be and since I got it for a less than $200 I'm very pleased. It's not showing any signs of dying out like before and runs very strong. I also replaced the discharge chute as the original one was cracked. It too was a cheap and easy fix. The hardest thing so far was repairing the pull starter since the assembly is riveted on. I ended up using an angle grinder to grind out the rivets in order to repair the cord. I thought briefly about trying to replace the rivets with screws but I ended up just using rivets again even though I had to grind them down on the inside of the assembly once they were installed. Sorry to be so long winded on my first post but I've had this machine for almost a year now and I've read countless posts on this issue and wanted to give my two cents and hope it helps someone out there that may still have issues with theirs. It's not a very complicated job to do and as long as you have basic tools and skills it can be done. Just take your time. Take care all and I'm glad to have found this site!


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## Kiss4aFrog

Really good info Thombat. :hope:


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## HCBPH

Another possible issue is the gas cap. Some don't let air into the tank and it will starve the engine. Try loosening the cap and see if that makes a difference.

One other thing, I'm assuming that has one of those non-adjustable jet carbs on it. I've changed more than one out for an Oregon adjustable one for a comparable size engine. Just make sure you get one with the right throttle and choke linkage or swap out the ones from your current carb. It's alot less frustrating as some of the newer carbs I can't get to work right while these work first time.


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## conwaylake

*carb or coil*

loridinnx2000 

Since you say you've 'rebuilt/cleaned' the carb many times, but have not yet replaced it, 
I strongly suggest that you REPLACE the carb with the recommended carb kit Briggs & Stratton 590907. 
It is a different carb.

thombat4, So a new coil fixed rough running ? Oh well, I stand slightly corrected. Most importantly is what worked for you... 
I had my new coil at the ready, but the carb kit is what did it for me. 

lorindinnx2000: take your pick or just go fer it and do both (carb and coil). 
Do you really want to troubleshoot when weather is not 92F like it is today in Mass ? 

and give that fuel system a good tear down and cleanout as well! 

Good Luck, and please keep the forum posted with your progress....


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