Snowblower still stalling under load

I've posted this last year and it seems that no matter what I do I can't get the problem solved. I have a 33" Noma snowblower with a tecumseh 12 hp motor, model # OHSK120. It starts on the first pull and runs perfect until load is applied. I used it this morning on 4 inches of moderately wet snow and it threw the snow for 3 minutes and then started backfiring and stalling. I got it started by pushing the primer once, wouldn't start without priming. It ran for 2 minutes and the same thing happened. I tried this 6 times and gave up. The carb model is a tec 640105 which replaced tec 632536. I completely rebuilt it over the summer with a new rebuilt kit. I socked it overnight in lacquer thinner before installing the kit. I am going to buy a new carb and just wanted to check to make sure that it was in fact the problem and not something else. Any feedback or help would be greatly appreciated.

 

Before you buy a carb,, make sure you have a good flow of fuel to the carb.. Also try it with the gas cap loose incase it's blocked... Do you have spark as soon as it quits??? You may have an ignition problem when the module heats up... Check into these first & let us know what you find....Roger

 

If you went to the trouble of rebuilding it, you probably made sure of the fuel flow to the float bowl on it? And with that you would have adjusted the load screw?

It sounds more like either the above or the ignition coil is failing. I would check for spark when it conks out and use a new plug.

I would bet a new carburetor won't fix it.

 

I was under the impression that the carb had no adjustments. Is there a procedure to adjusting the load screw? Just to confirm, the easiest way to check for spark is to pull the plug, insert it into the plug wire and try to start it to see if there is spark? Sorry for the ignorance.

 

Yes,, pull the plug,, insert it in the wire,, ground it & check for spark as it's cranking... For intermitant problems, I like an inline air gap tester that you can see when the engine is running (~$4.oo at parts stores) & as it starts to stall you only have to look @ the tester to see if it has spark & even what color the spark is..... Roger

 

Last night I went to check the spark plug to make sure it was in good shape. It was new last year. After unplugging the wire the spark plug was loose and so was the tip on wire side. Could this of caused the problem? I think so can't be certain. Just want some expert opinions. Thanks again.

 

The plug tips being loose can cause backfiring or "skipping". Replave the plug with a solid connector plug.