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

These are the sounds issued forth from my beloved Tecumseh engines equipped with fixed Jets. I don't own one but my friend does on a machine I recomended and he constantly rags me about it. In an effort to get him off my back I have researched the following and these are the results:

1) The replacement carb for a medium frame Tecumseh is 632334A ( this is a part # that replaces a disontinued part but the blow up diagram of the replacement shows an adjustable main jet. Therefore I ASSUME it is adjustable.

2) The carburetor repair kit for this model is 632347 

I was able to secure a blowup diagram of this carb and the list of parts in the repair kit. It APPEARS all of the main jet parts are present in the kit.I NEED VERIFICATION If this includes the needle and the jet. 

If one were to remove the fixed jet from the current carb which I believe is the green plastic tube held in by O-rings and replace it with the adjustable jet and needle from the #632347 repair kit would it work? Could you retrofit the new bowl with the adjustable assembly or would you have to buy a new bowl?

If anybody could verify or correct my assumptions I would be most appreciative.

Marc

Just for the record -theHonda GX series engine on my power washer made the same spit, sputter,cough,blemph sounds due to it's fixed jet carb. Honda has addressed this problem by producing a line of altitude related jets. Another words if you want to richen up a Honda fixed jet carb parts are available. The carb will still be fixed jet but at a richer setting.

Richie-

 Friends machine is new last season and runs great. Just suffers from the "fixed jet blues".

My point on the green tube is that I believe it takes the place of the adjustable jet . It's that part that you refer to as the brass tube going into the carb throat. It's the picture that Marty posts from time to time telling folks to clean the two holes with the bread wire. I may be wrong in calling it the adjustable jet but I have heard it referrd to as that in conversations with others. My hope is you pull the green tube and either refit the existing new style bowl with the the adjustable assembly  or purchase a bowl that will accept the adjustable assembly and that this will work.

If the adjustable mates up with the hole that the green tube was removed from I think you would have to leave the o-ring in the hole to prevent an air leak. The one thing that will tell if this scheme will work is to know if the green tube and the adjustable tube are the same length. Being that the bowls are the same depth and the carb housings are the same  there is a shot this will work.  

Are you sure the green tube is called an emolition tube.? I thought the emolition tube was the tube cast into the Tec. carb body that couldn't be removed. I remember it as the part you couldn't see but could hear rattling if you shook the carb next to your ear.

Marc

I thought Marty was talking about the bowl nut?

mml4 wrote:

Hi Mints!

The bowl nut is to my understanding part of the main jet assembly. That tube with the holes in it holds a needle valve that adjusts from the bottom. Kind of like the spray bar assembly on a model airplane engine.

Marc

nope it wont work...

the plastic tube that nobody can spell the name of is easily removed.as are the 2 o rings,that hold it in place.however the old style carb has a brass tube thats pressed in place.have never been able to get one out.

the adjustable high speed nozzle (thats on the bottom of the bowl) has a long thread and it runs up in the carb and mates in the brass tube.

the new  non adjustable also mates with the plastic tube but the lengths are different and the thread is not the same ( i think).

now that you are all dissapointed and cranky about it maybee i will just tell you how to repair the new emission style carb.

say please...

later chris 

ha ha the fix is in now.

now you all understand that the PLASTIC tube is where the fuel starts bubbling up into the throat of the carb...its that whole venturi deal that we learned in school.

the fuel is supposed to be evenly atomized and the engine is supposed to run at different temps and speeds.

thats a whole lot to ask from an engine with this style carb...BECAUSE  it must meet emission regulations.you guys in california are well used to this story.

so what do we do with the engine or the carb.

its basically running in a lean condition most of the time ,add some below 0 temps and its really lean.

no power and surging and hunting all over the place...

got you hooked yet

later chris 

we have to richen it up somehow...

those of you that are familiar with my teachings will already be on to the cure for the carb.

we cant change a bunch of stuff  ,its illeagle (sp).so it must look like its not been tampered with.

we dont want the emission police catching us now do we.

so we know that the plastic tube has some holes in it and the bowl retaining bolt may have 1 or more holes in it depending on hp

now the fuel has to flow through the hole and up into the venturi.correct.

we also know that these parts have been gummed up with some bad gas so we have to clean everyone of them .now some of the holes might be plugged a bit and we might just have to ream them out with a fine wire cleaner usually found in the tip cleaners with the acetylene torch gear.

everyone understand now,be carefull not to ream the holes to much or your engine will be to RICH.

later chris

Hi Chris,

Hi Chris-

Man  am I glad your computer got fixed! Thank you so much for the explanation. 

As always one explanation leads to another question. You mention that depending on hp the bowl nut on the new style carbs have a different number of holes. If we ordered the bowl assembly for a larger hp medium frame engine and put it on the low hp medium frame engine could we pick up some free ponys?

In a recent thread someone explored the hp ratings of Tec. engines and shared with us a conversation he had with a tech at Tecumseh.He was told  the difference in hp between engines of the same displacement was achieved only through jetting.

We brothers of the snow flake really  those "free" ponys,

Marc

you could yes ,

but i was speaking in general

covering more than one engine from 5 to 11 or 12 horsepower.

the ratings seem a little fudged to me anyway.

i shortblocked a snowblower and the same shortblock fits everything from an 8 to an 11 horse.

so whats the diff,carb, head ,cylinder head gasket and possibly iginition but i dont think so yet.

will check on it more.

i do know that the shortblock came with 2 headgaskets ,one being a bit thicker than the other.

later chris