Craftsman Snowblower only runs on choke

tjm0852 · 03-29-2009, 05:30 PM

So my craftsman model #536.881800 snowblower was only running on choke. As soon as I switch it over to run it would stall. I noticed that the bar to govern would engage and kill the engine. This started during this snow season and I want to get it fixed before I store it this year.

I removed the Carb and cleaned it up with carb cleaner, but that has not helped at all.

After I pulled the carb it would not start at all, so I pulled the spark plug out and put a tablespoon on gas in there. It started up but will still only run on choke. Spark Plug looks good and was replaced about a year ago.

There was no varnish in the carb and the gas is fresh and it has always been stored with fuel stabilizer in it.

It has a Briggs and Stratton carb with the number 21473 stamped on it. Anyone have any suggestions?

Tom Struble · 03-29-2009, 05:36 PM

i would get a carb kit with the diaphragm and a new plug
check the float mak sure its not heavy with fuel

tjm0852 · 03-29-2009, 05:42 PM

The float is not filled with fuel. I took it apart and shook it, it is empty.

What do you mean by diaphragm? I have the parts break out but do not see anything called a diaphragm.

Tom Struble · 03-29-2009, 10:13 PM

sorry your carb may not have one,i would try a carb overhaul kit but you should be aware that there are some carbs that have tiny passages that can be very difficult to clean,you could also have leaking welch plugs some carbs are just easier to replace

im not a small engine mechanic just a tinkerer so please wait for a real mechanic to help you with this good luck

Willie T · 03-30-2009, 04:14 PM

This may help point you in the right direction.

http://www4.briggsandstratton.com/mi...ence_Guide.pdf

Aggie67 · 03-30-2009, 04:31 PM

If everything else is cleaned like you state (no jets clogged, etc), then what's going on is the motor is being starved of fuel when you turn the choke off. Choke enriches the fuel/air mix. But if you had a situation where the motor was drawing in excess air, shutting off the choke will lean out the mix to the point where it stops igniting.

I'll bet you a sandwich that you need to replace the gasket between the carb and the manifold. You might be getting excess air in there after the carb, so the mix is unnaturally lean. This happened on my B&S 10hp pressure washer last spring. Once I replaced the gasket, it ran factory fresh. But if you're doing that, you might as well replace the jets. It takes 5 minutes.

Also, my fuel needle had two stages of jets, so inside the carb at the unchoked vacuum level it was pulling fuel through a lower set of jets, and in choke it pulled more fuel through another set of jets higher up the needle. If your carb was like my B&S, then maybe your lower jets are clogged, and the other ones aren't.

dcsanf · 04-12-2010, 09:48 PM

I purchased the craftsman model 536.881800 8 Horsepower Snow Thrower mainly due to the fact that it had a Briggs engine on it. I also purchased a Craftsman lawn mower and riding tractor at the same time because of the same reason. I had significant problems with my lawn mower engine last year resulting in a $100 repair bill due to some faulty carburetor issues and now my snow thrower keeps stalling out. I have taken extremely good care of these items draining and running till empty, using fuel stabilizer, winterizing or summerizing as the case may be. These products are also less than 5 years old. After having years of good experience with Briggs & Straton engines most of those having had zero preventive maintenance I am totally disappointed with my recent experiences and with what I have been reading regarding carburetor rebuild kits, etc.

Briggs is certainly not what I remember it being and I will never purchase another Briggs product again, although the competition is most likely no better. Sears will obviously do nothing, so I am stuck with $2000 worth of junk.

CoconutPete · 04-15-2010, 10:27 AM

Quote:

Originally Posted by Aggie67

If everything else is cleaned like you state (no jets clogged, etc), then what's going on is the motor is being starved of fuel when you turn the choke off. Choke enriches the fuel/air mix. But if you had a situation where the motor was drawing in excess air, shutting off the choke will lean out the mix to the point where it stops igniting.

I'll bet you a sandwich that you need to replace the gasket between the carb and the manifold. You might be getting excess air in there after the carb, so the mix is unnaturally lean. This happened on my B&S 10hp pressure washer last spring. Once I replaced the gasket, it ran factory fresh. But if you're doing that, you might as well replace the jets. It takes 5 minutes.

I will not quite bet you a sandwich, but i'll bet you my best hat this is the answer haha.

Yoyizit · 04-15-2010, 02:29 PM

Quote:

Originally Posted by Willie T

This may help point you in the right direction.

http://www4.briggsandstratton.com/mi...ence_Guide.pdf

You can add 'partially clogged high speed jet' to table #14.

Thurman · 04-16-2010, 05:59 PM

Errrr-have you tried to see if it will continue to run IF you spray WD-40 at the gasket where the carb unit attaches to the motor? Sure fire test for a leaking gasket at that area. Then if it does run--make Pete a sandwich. David