[hankster1228]

I have a new Craftsman 24" snow thrower. Its 1 yr. old. I changed the oil, gas, and spark plug. When i get it running. It sounds like the engine is pulsing. Its not a cosistant run. I can see the trodle on the carburetor going back and forth. The impeller assembly is turning and sprial ass. is working. but the engine does not sound right? do i need to adjust the carburetor? if so. how? thanks, Hank. snow is comming soon.

 

[2cycled fruitcake]

sounds like the engine is"hunting"or surging.
clean the carb 1st. if it doesnt improve.....
look for a screw above the carb float bowl,&while running turn it slowly inward&see if the engine smoothes out, then back off till it gags again, then in a1/4turn should keep it smooth.
its a bit of fine tuning to get it there.

 

[indypower]

Your carb has no adjustments to it. It is an EPA fixed jet carb. You have varnish inside the carb. Easy fix is to buy a bottle of Seafoam (at your local auto parts store) and add some to the gas (about 2oz/gal) and run the engine for 15-20 mins. or until it smoothes out.

 

[Jasper]

Hi Could also be that the govenor is not adjusted properly

 

[2cycled fruitcake]

govenor is likely,
i was assuming this unit had adjustable carb.....

 

[Ingersoll444]

Govenors dont normaly become unadjusted. The modern carbs used these days have very little tolerance for bad gas. That added to the fact that todays gas has a shelf life mesured in weeks not years... Ya... your carb is plugged. Try the seafoam trick.. if that does not do it you need a carb rebuild, or replacement.

 

[butchf]

Govenors dont normaly become unadjusted.

agree totally!
Although, if the initial setup is wrong it could be "out of adjustment".
The governor spring attaches to a fixed tab setting the tension for the governor. If it got bumped, it could cause the symptoms you are having.
Often times bending the tab VERY slightly will resolve the pulsations. I've seen a little as 1/32" change to completely clear the issue.
The newer 4 stroke carbs don't seem to be as problematic as the older 2 strokers when it come to old fuel.
My 11.5 HP 28" Craftsman sat all summer with old fuel and starts on the first pull. I don't even need to use the electric start........lol
Heck, my 1979 Toro sat with pre-mix all summer and starts right up.
Then my other Craftsman 5/22 had a big issue last year similar to you.
I cleaned and rebuilt the carb with all new parts and it still would not adjust right. Then I remembered I had put in a new oring for the needle adjust. Having experienced this problem on Toro's in the past I recovered the old ring and installed it. Bingo! It now adjusts perfectly.
As it turns out, the original ring does not have a round profile. It is more like square shape with a taper ring. All of the replacements from Craftsman, Briggs, and Tecumseh are a round profile and in some cases do not work. I've ordered them from all 3 sources and from my local dealer. I shared this with my Toro dealer and he was able to resolve a few difficult machines at his dealership. We tried changing the needle, needle spring and washer with no effect. I now save all the old ones just in case.
I just hope this helps someone else....

 

[butchf]

? Does it change under load?
? How does the choke effect it?
? Is the carb tight to the gasket?
? Is the muffler tight to the gasket?

Each of these areas can cause the symptoms.

Quote from Charles F. Kettering....."once found, all solutions are simple"