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2 stroke engine running poor - need a little help...

aces-n-eights's Avatar

Join Date: Oct 2013
Posts: 92

01-22-18, 01:44 PM   #1  
2 stroke engine running poor - need a little help...

I have a Crafstman 3HP, 21" single stage snow blower. It's a 2 stroke engine. The engine starts right up but only really runs with the choke on full. Obviously is doesn't have much power, so if the snow is wet and heavy, it stalls out.

I've sprayed some choke cleaner in it as it's running and run some Seafoam in the fuel.

I looked up the parts and a replacement carb is $76.

Any ideas on what to try before i pop for a new carb? Is the problem even related to the carb?


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Keith Grayson's Avatar

Join Date: Jan 2018
Posts: 15

01-22-18, 02:02 PM   #2  
If the engine runs with the choke partially on this indicates you have an obstruction that is restricting the gas flow up through the main jet in the carb, this only sucks up fuel due to airflow across the port, a pressure drop is created which sucks the ful up out of the fuel bowl on the bottom of the carb, this is a very wek effect which is amplified by application of the choke creating a greater pressure drop and sucking more fuel past the obstruction of the main jet, the engine will run however at about 1/2 speed and often just kills the motor if you floor the throttle, this requires removal of the carb and reaming the orifices with a strand of electrical wire, spray carb cleaner through each port and orifice and replace the carb, this is a very common issue, even with a new carb if you store the unit with gas in it and do not run it dry prior to storing it this can be an annual event, fuel stabil also helps from gumming up the works.

aces-n-eights's Avatar

Join Date: Oct 2013
Posts: 92

01-22-18, 02:34 PM   #3  
Thanks Keith, appreciate it. I'll probably take it off and give it a good cleaning.

Pilot Dane's Avatar
Group Moderator

Join Date: Mar 2003
Posts: 16,684

01-22-18, 02:53 PM   #4  
I agree it sounds like a classic dirty/clogged carburetor. Before you take anything apart use a digital camera or the camera on your phone to take pictures of the carburetor's hoses and linkages so you can connect them back up properly. Also take pictures at each stage of disassembly. Pictures are free so don't be stingy. There can be some tiny bits that must be reinstalled properly.

joecaption's Avatar

Join Date: Jan 2011
Posts: 3,967

01-22-18, 03:18 PM   #5  
A 2 stroke, 3 HP snow blower, Hmm.
I agree with all the other posters it's a carb issue.
Any seasonal power tool like that should be using non eternal fuel for far less fuel related issues!
At the end of the season let it run completely out of fuel before storing.

geogrubb's Avatar

Join Date: Jun 2006
Posts: 2,333

01-22-18, 05:06 PM   #6  
We need more info, do you have the model number of the blower or the model numbers for the engine, does it have a diaphragm or bowl type carb, Have a good one. Geo

Wirepuller38's Avatar

Join Date: Feb 2006
Posts: 6,190

01-23-18, 06:19 AM   #7  
Inspect the muffler to make sure it is not partially clogged.

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