HS40-55388C Carburetor?

#1
I bought this engine and was wondering if this is the correct carburetor , if so I would like to rebuild it but I'm not sure what parts number the carburetor is . Can anyone identify this from the pictures and is it correct ?

Thanks for any help,
Mike Part_1 (1).jpeg 20190213_142113.jpg Part_1 (2).jpeg Part_1.jpeg
 

markus

Well-Known Member
#2
Yes it is a correct original carb for an hs40 55388c, the carb number is 631667, to verify that you can use the stamped number on the carb body there is a link to the tecumseh carb number stamping guide located in the sticky threads here in the tecumseh section.

you can find the parts breakdown for the carb by using the engine model number just like you are searching for engine parts. There will be a separate section that will break the carb down by part: 631667 carb info

you will want to try and use genuine parts when possible on the basic rebuild kit. Much better quality than the aftermarket kits. Before doing anything extensive you want to make sure the gutted body (take off the bowl, and float parts and shake the body up and down. If it does not rattle you will have a problem in the low sped idle circuit I can show you how to get in there if that is the case, just post back up on here whern you get that far in.
 
#4
Yes it is a correct original carb for an hs40 55388c, the carb number is 631667, to verify that you can use the stamped number on the carb body there is a link to the tecumseh carb number stamping guide located in the sticky threads here in the tecumseh section.

you can find the parts breakdown for the carb by using the engine model number just like you are searching for engine parts. There will be a separate section that will break the carb down by part: 631667 carb info

you will want to try and use genuine parts when possible on the basic rebuild kit. Much better quality than the aftermarket kits. Before doing anything extensive you want to make sure the gutted body (take off the bowl, and float parts and shake the body up and down. If it does not rattle you will have a problem in the low sped idle circuit I can show you how to get in there if that is the case, just post back up on here whern you get that far in.
Thank you Markus, that is awesome and I did what you said took the float bowl off and did hear a rattle , so now i will get some Tecumseh parts and get on the rebuild then off to the engine , lol.
 

markus

Well-Known Member
#5
Thank you Markus, that is awesome and I did what you said took the float bowl off and did hear a rattle , so now i will get some Tecumseh parts and get on the rebuild then off to the engine , lol.
excellent! If you are new to working on the small engines in general A set of welding torch tip cleaners are handy for when doing the rebuild of these carbs, to help clean out all the tine passages (the one associated with the idle circuit that Rattles that is in the threads for the high speed circuit can be the toughest to clean/get into). The actual Tecumseh carb tool is pretty awesome too, it will pull the needle seat as well as properly reseat it, and you can set your float level with it too. It's not a necessity by any means as all that can be done other ways, but its a nice tool to have if you mess around with these.

Don't forget your throttle shaft as well. that is the highest wear point and cause a lot of tuning problems since it will suck air into the intake as well as not seat the butterfly/throttle plate. They will normally wear out the shaft more so than the carb body thankfully with the original softer brass shaft.

Typical worn brass one on the bottom:



When you get into the rebuild in the engine you may run into the same issue on the engine block with concern to the governor pivot shaft. Although in those you usually need to drill and insert a bushing into the block and sometimes replace the shaft as well dependent on the wear it has.

Good luck with it!
 
#6
excellent! If you are new to working on the small engines in general A set of welding torch tip cleaners are handy for when doing the rebuild of these carbs, to help clean out all the tine passages (the one associated with the idle circuit that Rattles that is in the threads for the high speed circuit can be the toughest to clean/get into). The actual Tecumseh carb tool is pretty awesome too, it will pull the needle seat as well as properly reseat it, and you can set your float level with it too. It's not a necessity by any means as all that can be done other ways, but its a nice tool to have if you mess around with these.

Don't forget your throttle shaft as well. that is the highest wear point and cause a lot of tuning problems since it will suck air into the intake as well as not seat the butterfly/throttle plate. They will normally wear out the shaft more so than the carb body thankfully with the original softer brass shaft.

Typical worn brass one on the bottom:



When you get into the rebuild in the engine you may run into the same issue on the engine block with concern to the governor pivot shaft. Although in those you usually need to drill and insert a bushing into the block and sometimes replace the shaft as well dependent on the wear it has.

Good luck with it!
Dang , I wish you didn't know so much I would have had this done in no time and not working , yes I can feel the play in the throttle shaft, I do have some experience rebuilding just not such an old carb, luckily I did pick up some cleaning tips this past summer. I will get the shaft ordered and off to the Block, it did seem like there was a lot of play in governer , arrgghh .
Thanks again Markus
 
#7
excellent! If you are new to working on the small engines in general A set of welding torch tip cleaners are handy for when doing the rebuild of these carbs, to help clean out all the tine passages (the one associated with the idle circuit that Rattles that is in the threads for the high speed circuit can be the toughest to clean/get into). The actual Tecumseh carb tool is pretty awesome too, it will pull the needle seat as well as properly reseat it, and you can set your float level with it too. It's not a necessity by any means as all that can be done other ways, but its a nice tool to have if you mess around with these.

Don't forget your throttle shaft as well. that is the highest wear point and cause a lot of tuning problems since it will suck air into the intake as well as not seat the butterfly/throttle plate. They will normally wear out the shaft more so than the carb body thankfully with the original softer brass shaft.

Typical worn brass one on the bottom:



When you get into the rebuild in the engine you may run into the same issue on the engine block with concern to the governor pivot shaft. Although in those you usually need to drill and insert a bushing into the block and sometimes replace the shaft as well dependent on the wear it has.

Good luck with it!
The governor shaft does have play , I'm guessing that putting a new bushing in the block would require precision drilling , i only have hand tools ?
 

markus

Well-Known Member
#8
The governor shaft does have play , I'm guessing that putting a new bushing in the block would require precision drilling , i only have hand tools ?
rebushing the block is actually pretty easy with no real special tools needed. I did 2 of them last week and have to do a couple more probably next week after I get these two current ones I just did farrther along into longblocks and off the workbench. I'll snap some photos when I do those and pass the info along to ya!
 
#9
The governor shaft does have play , I'm guessing that putting a new bushing in the block would require precision drilling , i only have hand tools ?
The governor shaft does have play , I'm guessing that putting a new bushing in the block would require precision drilling , i only have hand tools ?
I did see your other post regarding governor shaft , Mine doesn't not to seem nearly that bad as one in photo , I will purchase new shaft then decide if i need to go with bushing.
Thanks again.
 

markus

Well-Known Member
#10
I did see your other post regarding governor shaft , Mine doesn't not to seem nearly that bad as one in photo , I will purchase new shaft then decide if i need to go with bushing.
Thanks again.
Yea that one was the worst I have ever seen (on a reusable block) I started to just do them on anything I have that shows a little wear in the block now just for good measure......the 3.5hp longblock I did the other day I removed the internal governor parts so it wasnt ever really big factor :D I just did it to retain a really smooth operating pivot point and hopefully not a heavy leaker at that point under heavy load if the stock throttle assembly gets used.

 

markus

Well-Known Member
#12
Stock rod polished? You always have the nicest parts "pile"!
Yea, that rod had some excessive cast flashing and one spot I could not tell if it had air bubbles in it or not so I filed all the flashing off to make sure there were no problems. I smoothed and polished the outside edges that the seam was on so there would be no scratches or gouges. I dont know were those small frame h25-h35 I beam rods fail, but I noticed that they beefed up the wrist pin area around the pin and into the beam a little over the older versions. but kept them dinky at the crankshaft journal.

 
#13
Yea that one was the worst I have ever seen (on a reusable block) I started to just do them on anything I have that shows a little wear in the block now just for good measure......the 3.5hp longblock I did the other day I removed the internal governor parts so it wasnt ever really big factor :D I just did it to retain a really smooth operating pivot point and hopefully not a heavy leaker at that point under heavy load if the stock throttle assembly gets used.

I will probably put a bushing in it, may as well do it correctly sure don't want oil leaking especially after putting so much time into cleaning every bolt and nut on my bike . I did get it sandblasted last night, guess I will look for someone to hone the cylinder then decide next course of action. I'll admit I was tempted to just buy all new internals and call it a day , this project has taken much longer than expected as do all my projects . Today need to work on girlfriends car after she got rear ended.
 
#14
Yea that one was the worst I have ever seen (on a reusable block) I started to just do them on anything I have that shows a little wear in the block now just for good measure......the 3.5hp longblock I did the other day I removed the internal governor parts so it wasnt ever really big factor :D I just did it to retain a really smooth operating pivot point and hopefully not a heavy leaker at that point under heavy load if the stock throttle assembly gets used.

Wish I had started this rebuild 20 years ago when i bought it , parts would have been so much easier to come by, lol.
 
#15
Markus , on the float bowl shaft is there supposed to be a spring , in the parts diagram it shows one but they don't offer it for sale , they also show a spring and two washers on the choke shaft ?
 

markus

Well-Known Member
#16
The parts breakdown pictures are just generic so it just shows a basic series 1 carburetor. If its not on the written part of the list, it didn't get it.
 
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