Craftsman snowblower

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  #1  
Old 01-24-04, 04:04 PM
sidvicious
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Craftsman snowblower

The craftsman 3hp 20" snowblower model#536.884351 is not running right, When the choke is set to off position after warming up the engine surges then dies down, then surges again. I can see the rpm adjusting lever along with the air vain and governer ling going back and forth with the surges. I took off the gas tank and cleaned the lines. I took of the float bowl assembly and cleaned the high speed bowl nut. The model number of the engine is 143.943071 carburetor # 632560a. I can hold open the governer and it peaks but I just can get it to run steady at the high speed for throwing snow. Any help would be appreciated as I am just a little bit handy. Thanks...Sidvicious
 

Last edited by sidvicious; 01-24-04 at 04:19 PM.
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  #2  
Old 01-24-04, 08:01 PM
sidvicious
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craftsman surges

well I've been going over everyone else's problems with the surging of the moter and it seems like I need to take a closer look at the high speed adjustment screw/bolt that goes through the float bowl. I did take it out but only saw one hole toward the bottom which was clear. I will look for other holes on the bolt to see if they are clear. I did not know though, and I'm still uncertain that the screw, "high speed" botl/screw is the one on the outside bottom of the carb bowl. It was tightened all the way into the bowl so thats how I replaced it. Should back this bolt out while running? Thanks anyone????
 
  #3  
Old 01-24-04, 10:42 PM
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Hello sidvicious!

Yes. the high speed adjustment screw is under the carb bowl. It shouldn't be tightened all the way if it is a screw that goes through the center of the bowl nut. While the engine is running at full throttle, back the screw out until it runs rough, then screw it back in until it begins to surge while counting the # of turns it takes to do this, then back it out half that many turns. It usually winds up being around 2 1/2 to 3 1/2 turns out from lightly bottomed.
 
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Old 01-25-04, 06:03 AM
sidvicious
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thanks cheeze...I'll try it after church this morning. We are expecting snow today so cross your fingers.
Thanks,
Sid
P.S. other research has told me that the gas cap hole/vent should also be cleared and that due to the changes in gasoline, you should run the motors with the choke partialy on(according to briggs & straton). I don't think I should though!
 
  #5  
Old 01-25-04, 08:55 AM
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sid
If and when the carb is set correctly, you shouldn't have to run with the choke on (even partially) You only need the choke to give the engine a rich fuel mixture during startup.
Regarding the holes in your high speed nut there is a larger one that you saw already but there should be one other that usually plugs up. It will be above ,but maybe not directly inline with, the larger one. The hole size for that one is approx. .020 and it may be a little hard to see but it should be there.
Once you clean that, do what cheese says and you should be ready to go.

snoman
 
  #6  
Old 01-25-04, 05:37 PM
sidvicious
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Well gents I still don't think I have it completely fixed. I removed the high speed adjustment screw and I can only find one hole(I used a magnifling glass) with the exception of the one running through the center. I tried to back it off to adjust but it has to be tight to hold the bowl on, otherwise it leaks gas. Remember I only have one speed on this type of snowblower. It seems to be running fairly well with a partial choke on but I'm still not happy and we have not gotten our snow yet. When I turn the choke completely off it does not run steady and surges up and down, but not a bad as before.
 
  #7  
Old 01-25-04, 11:22 PM
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Ok, there are two types of bowl screws. One has no high speed adjustment screw and if you loosen the bolt (takes a wrench) it will leak. The other kind that has the adjustment screw is like a bolt with a small screw (takes a flat screwdriver) going up through the middle of it. If you are surging, it is not getting enough fuel for whatever reason. You can try loosening the fuel cap, but I don't think that's the problem since you don't mention it running fine for a while before surging. You still have a carb problem.
 
  #8  
Old 01-26-04, 02:14 PM
sidvicious
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The type I have does not have any other screw "built into" the main bolt. Is there a gas additive that I could add to the gas to "possible" clear out any remaining blockages? It's my niebors snowblower and I'm not confident enough to tear it down to the point where I can take the carb off and clean it right. We'll find out soon enough here in Jersey if I did enough to keep it working
 
  #9  
Old 01-26-04, 02:28 PM
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sid
After looking at the drawing on Sears for your machine, I believe that it is a 2 cycle motor (you have to mix oil with the gas) and when looking in the service manual that I have regarding the 2 cycles, yours most likely has a "fixed main jet" (high speed) in other words you have a brass colored nut at the bottom of the float bowl that you probably use a 7/16 " wrench to remove and no adjustable screw going through the center of it. So you cannot do any type of adjusting of the high speed. Like cheese says, I think the problem is in the very tiny orifices inside the carb that have become plugged or varnished over time due to gas being left in the carb. The best way is to completly remove the carb, soak it and install a carb kit. But you can check out your local small motor dealer and see if they have an aerosol type of carb cleaner that can be used on your 2 cycle without causing any problems elsewhere in the engine.
Hope this helps you.

snoman
 
  #10  
Old 01-28-04, 03:02 PM
tidajo
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surging

If it's a Tecumseh engine (most sears kind were), go to
http://www.cpdonline.com/692509.pdf
it's the Tecumseh technicians manual, that you can view/ print online.
I found it today after surfing around to solve my carb problem.
I did see something in the troubleshooting section about the surging and carbs.
Good Luck!
 
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