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Tecumseh carburator adjustment


Lewjac's Avatar
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01-28-09, 09:23 AM   #1  
Tecumseh carburator adjustment

I have a ten year old MTD with a HMSK100 159295V motor, I did a little research and believe the carburetor number is 632370A. I had a problem with the engine stalling and making a popping sound after the engine gets hot, I cleaned the carb by spraying it while running and it seemed to help a little.There are two screws that I can see for adjustments, one is on the side and one is under the bowl, I turned the one on the side clockwise until it was going to stall and back it out one turn it didn't seem to make a difference. Can anyone tell me if there are any other adjustments I can make, like the screw on the bottom of the bowl?

 
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cpgixxer's Avatar
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01-28-09, 01:45 PM   #2  
Posted By: Lewjac I have a ten year old MTD with a HMSK100 159295V motor, I did a little research and believe the carburetor number is 632370A. I had a problem with the engine stalling and making a popping sound after the engine gets hot, I cleaned the carb by spraying it while running and it seemed to help a little.There are two screws that I can see for adjustments, one is on the side and one is under the bowl, I turned the one on the side clockwise until it was going to stall and back it out one turn it didn't seem to make a difference. Can anyone tell me if there are any other adjustments I can make, like the screw on the bottom of the bowl?
The one on the side is an air idle adjustment. The one on the bottom is the main jet (high speed) adjustment, if you messed with that one and it made no difference then it is dirty, needs to be taken apart and soaked in carb cleaner ( the whole carb should be cleaned) .

 
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01-28-09, 02:18 PM   #3  
Intial adjustments are 1-1/2 turns out on both screws. With engine off, turn the screws in until they are LIGHTLY seated. Then back out 1-1/2 turns.
Like cpgixxer noted, the one on the side is the idle adjustment. This must be adjusted with the throttle at 1/2 or lower. This screw has little or no effect when running wide open.
The bottom screw is the high speed and that one needs to be adjusted with the engine running at full throttle.
I also agree that the carb needs to be taken apart, soaked, then reassembled with a new carb kit. Sounds like the carb is varnished up inside.

 
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01-28-09, 03:40 PM   #4  
Thank's to all for your advise!

 
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01-29-09, 04:20 PM   #5  
Just wondering if anyone knows where I can find instructions for rebuilding a Tecumseh 632370A carburetor on the web?

 
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01-29-09, 05:54 PM   #6  
Posted By: Lewjac Just wondering if anyone knows where I can find instructions for rebuilding a Tecumseh 632370A carburetor on the web?
Really not much to it.

1. Go buy a genuine tecumseh kit, bring in your motor #. This is assuming you removed the carb, take pictures, can't tell you how many guys mess the reconnecting of the rods back up. The rods will come off without removing governor control. Removal of the muffler makes the job much easier. Make sure you don't snap the bolts taking off the muffler, use penetrating oil between the head and the muffler and they should loosen.
2. Remove the bottom float bowl nut. The replacement kit comes with one, I keep them just in case.
3. Pull the bowl off the bottom with the carb inverted, discard the rubber ring that seals the bowl. Look at how the needle is on the float, open side of the needle holder goes toward the choke.
4. Pull the pin out from the float, shake the float to make sure it doesn't have gas in it, the replacement kit does not come with one.
5. Put carb in a vise, there is a plug in the bottom of the carb, it is a welch plug, use a thin wall punch, punch through it a twist it out. You can do the one on the outside but I don't.
6. Remove the idle jet screw, save the brass washer, new kit doesn't come with. Blow compressed air into the where the fuel line connects to the carb. The seat will fly across the room if you don't catch it, or use a long screw to pull it out if you don't want to save it.
7. Put the carb in good carb cleaner, submerse it. (2-3 hours depending on condition)
8. Remove it and wash it with soap and water. Use spray carb cleaner if you can't get the gunk off with soap and water.
9. Blow out passages with compressed air. If it's really dirty you may have to use a twist tie to clean the small holes on the inside of the carb. I use a toothpick in the main jet tube to clean out rust.
10. Install welch plug, concave side out. I use a 3/8 drive extension to drive them in. Seal the plug diameter with your wife's clear nailpolish, she will look at you sideways when you ask for it, mine did the first time.
11. Put a little oil on the seat, install groove side down, use a proper size punch to push it down until it seats.
12. Put the needle spring onto the float the way it came off, line the float up and put the pin back in the body and the float. Measure between the body and the top of the float with a 11/64 drill bit, this is the proper float height, if you need to adjust slightly use a flat blade screw drive to bent the float up or down.
13. Put the rubber gasket on the bottom of the carb, put the bowl on with the deepest part pointing where the float sits.
14. Put the bottom screw in with the gasket, DO NOT OVERTIGHTEN, they seat and thats it, you crank it, it will snap.
15. Screw in the idle screw, remember to replace the rubber o-ring and install with the brass ring you saved from the old one.
16. Screw in both idle and main get screws, they say back them out 1 1/2 turns, I do 2 turns.
17. Reinstall on blower, make sure your gasket is new and the surface is clean on the intake.

If the carb leaks the float isn't shutting off the gas, if it doesn't then it should start, 1 or 2 shots on the prime should do it. Adjust the screws by listening, they run like ass if they don't get enough or get too much fuel, it's all by sound and experience.

Hope this helps you.

 
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01-29-09, 06:25 PM   #7  
Posted By: cpgixxer Really not much to it.

1. Go buy a genuine tecumseh kit, bring in your motor #. This is assuming you removed the carb, take pictures, can't tell you how many guys mess the reconnecting of the rods back up. The rods will come off without removing governor control. Removal of the muffler makes the job much easier. Make sure you don't snap the bolts taking off the muffler, use penetrating oil between the head and the muffler and they should loosen.
2. Remove the bottom float bowl nut. The replacement kit comes with one, I keep them just in case.
3. Pull the bowl off the bottom with the carb inverted, discard the rubber ring that seals the bowl. Look at how the needle is on the float, open side of the needle holder goes toward the choke.
4. Pull the pin out from the float, shake the float to make sure it doesn't have gas in it, the replacement kit does not come with one.
5. Put carb in a vise, there is a plug in the bottom of the carb, it is a welch plug, use a thin wall punch, punch through it a twist it out. You can do the one on the outside but I don't.
6. Remove the idle jet screw, save the brass washer, new kit doesn't come with. Blow compressed air into the where the fuel line connects to the carb. The seat will fly across the room if you don't catch it, or use a long screw to pull it out if you don't want to save it.
7. Put the carb in good carb cleaner, submerse it. (2-3 hours depending on condition)
8. Remove it and wash it with soap and water. Use spray carb cleaner if you can't get the gunk off with soap and water.
9. Blow out passages with compressed air. If it's really dirty you may have to use a twist tie to clean the small holes on the inside of the carb. I use a toothpick in the main jet tube to clean out rust.
10. Install welch plug, concave side out. I use a 3/8 drive extension to drive them in. Seal the plug diameter with your wife's clear nailpolish, she will look at you sideways when you ask for it, mine did the first time.
11. Put a little oil on the seat, install groove side down, use a proper size punch to push it down until it seats.
12. Put the needle spring onto the float the way it came off, line the float up and put the pin back in the body and the float. Measure between the body and the top of the float with a 11/64 drill bit, this is the proper float height, if you need to adjust slightly use a flat blade screw drive to bent the float up or down.
13. Put the rubber gasket on the bottom of the carb, put the bowl on with the deepest part pointing where the float sits.
14. Put the bottom screw in with the gasket, DO NOT OVERTIGHTEN, they seat and thats it, you crank it, it will snap.
15. Screw in the idle screw, remember to replace the rubber o-ring and install with the brass ring you saved from the old one.
16. Screw in both idle and main get screws, they say back them out 1 1/2 turns, I do 2 turns.
17. Reinstall on blower, make sure your gasket is new and the surface is clean on the intake.

If the carb leaks the float isn't shutting off the gas, if it doesn't then it should start, 1 or 2 shots on the prime should do it. Adjust the screws by listening, they run like ass if they don't get enough or get too much fuel, it's all by sound and experience.

Hope this helps you.
CP, Just want to thank you for the information! Appreciate your reply. I rebuilt two carbs in the 70's Ford and GM, this seems more involved, I don't remember them having welch plugs, if I am correct the Ford had an diaphragm the GM didn't?

 
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01-30-09, 04:47 AM   #8  
Posted By: Lewjac if I am correct the Ford had an diaphragm the GM didn't?
Could be , I was born in 75 so I'm an injection kinda guy. My dad would know, I know the chevs don't have diaphrams.

 
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