Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I recently picked up a Airens ST1032 snowblower. It is in good shape but, when I bought it it was taken apart. The previous owner said it did not have any spark. I replaced the points and condenser and I also removed the cylinder head cover to check the condition of the piston and valves. They look good but i did notice a hair line crack in the cylinder head. (the part the spark plug screws into). It does not appear to go all the way through.

I am in the process of putting the motor back together, but with the cylinder cracked, I am also considering getting a new motor all together. How do i know if the head is trashed? It does seem to have a decent amount of compression, but it hard to tell, because i dont know what "normal" is for that motor?

It is a 10hp tecumseh HM100 motor

Any advice?

  The HM100 and HM80 used the same part number head and there are scads of junk HM80s around.  An ST with an HM100 at 32  is probably an 924xxx model with cast iron gearbox, differential, big tires and a super machine.  As a basket case you probalby got it for 50 bucks.  With rings and a valve lap that thing would be a tiger.

  I guess it would come down to how you feel about it but it could fail under load and cause some damage like a chunk getting into the chamber.  You are in there so swaping out the head now would eliminate a possible mid-season failure later.  It would not be so expensive and it's the end of the season so the added down time not a big deal.  

I am going to look into getting a replacement head for it. What do you mean be a cast iron gearbox? It does have the big tires, and the differential that can be changed for more traction.

The gear box came in three types in 924xxx's, two cast iron and one aluminum.  Many of the 1032's around are cast iron.  

     Those cracks may be just "Casting Marks"... if they were cracks, they would go (I think) all the way through with nothing to stop it.  Also if they were cracks comming off the plug hole,  The spark plug would expand them as it tightened up..

Remember what you said first... It has no spark... Put it back together and check your kill switch wiring and lockouts...

Good Luck,

Friiy

I got it back together tonight and it does have spark now. Replacing the points and condenser did the trick. Tomorrow morning I am going to see if i can get it running.

I can get a replacement head for $30, so I may get one anyway.

The cast iron gear box, is that in the front of the machine, up by the auger? If so, yes it is cast iron.

I have an Ariens 1032 as well. I go along with one of the other posters. What you are seeing on the combustion chamber side of the head could very well be a casting mark. It would be rather unusual to have a cracked head in my opinion. You would strip the treads out of the plug hole before over tightening a plug would ever crack the head. And if you've got good compression that would be another good sign in your favor. When you get it running you will know for sure. I believe that I have a used head off a Tecumseh 10hp. But I'll have to check to make sure. Keep us posted.

I got it running today, but it wont stay running. I soaked the carb for 2 days prior to today, got a carb rebuild kit, blew out all the carb with compressed air.  It will run on full choke, but when i turn the choke off, it stalls. I spent a few hours today adjusting the carb, but no luck.

I took the carb off of my st824 and (appears to be the same one) it started up and was running normal. So its definetly the carb. Any suggestions?

I was looking at new ones....

Pull the sick carb apart and clean it thoroughly.  Check your pilot and main jets for blockage.   Usually, the choke or enrichening circuit bypasses the normal fuel feed to dump higher concentrations of gasoline into the venturi to assist with quicker starting.  If the engine is running while choked but shuts down without it, your pilot and main jets are probably blocked.
Download an exploded view diagram for your carb to see how it comes apaprt.  Sometimes it's difficult to understand how the jets come out on some carbs. 

Where can I get the diagram that show hows the carb comes apart?

The motor is a hm100 159024D

  It's probably just some left over dregs and the carb will cleanup and be fine after another basic run through.  I dip in two solutions for 24 hours, give it an ultrasonic bath, then wash with carb spray then compressed air.  Occasionally it will act just like yours and it ends up some crud was missed.  I re-do the basics below and it's usually enough to get it going properly.   The chances of needing a new carb around about 200:1.

http://outdoorpowerinfo.com/repairs/tecumseh_carb_632334a.asp

 

Running a quart of gas through the tank out of the carb line to flush crud in the line that often causes problems.  Catch gas in a white cup and look for crud.  Often I'll run a half gallon through but still end up with bowl dregs after putting the carb back on.  The dregs are usually bits from the gas line that get loose from handling and break off later.

 

Spray through the carb inlet, both directions with the inlet line removed.

 

Check the carb seat is ribbed side in and fully seated.

 

Take the needle out of the bowl nut and spray in there.  Clean both holes in the nut with a thin wire, i.e. stripped tie wrap.  One is tiny and just above the bottom threads where the smooth area starts.

 

Run a thin wire up into the main tube i.e. runs from the bottom of carb into the throat.  Put slight bends in the tube so they just graze the tube inside.  Stick the carb spray tube at the tube and spray up into it.

 

Remove the choke butterfly and run a wire in the main jet air inlet at the base of the choke butterfly.  At least stick the carb spray tube there and spray in.

 

Check the float setting for 11/64 between rim and float with the carb turned upside down.  Use a drill of that size laid across the bowl rim. The float should just touch the drill.

 

Check if the needle is sticking on the seat by moving the float up and down a few time and watching the needle.  It may stick lightly but pull off as you lower the bowl.

 

Spray into the primer port and watch the flat on the outside of the carb just above the low idle adjust for a spray out of the air vent hole (tiny).  Also spray in the base welch cutout by the main jet base and watch for a fluid out of the same hole.

 

Remove the idle jet and spray in there.