New Tecumseh HS40 carb(s)

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cfh

Well-Known Member
#21
#21
In summary, all three carbs worked fine. I didn't really notice one that was better than another. The Amazon carb https://www.amazon.com/gp/product/B077M7NYB6/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 was probably the most work to adapt. It did have the advantage of the spring loaded float bowl drain plug. But required a different choke mechanism and plugging/enlarging of two holes. And frankly didn't really see any advantage to the performance.

The other two ebay carbs, #631921 (via ROP) and #631918 seemed pretty equivalent. I could not notice any performance differences. Since others seem to like the ROP (rugged offroad products) carb and have had good luck with it, that's the one I'll probably stick with.
 
capguncowboy

capguncowboy

Well-Known Member
#22
#22
cfh said:
In summary, all three carbs worked fine. I didn't really notice one that was better than another. The Amazon carb https://www.amazon.com/gp/product/B077M7NYB6/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 was probably the most work to adapt. It did have the advantage of the spring loaded float bowl drain plug. But required a different choke mechanism and plugging/enlarging of two holes. And frankly didn't really see any advantage to the performance.

The other two ebay carbs, #631921 (via ROP) and #631918 seemed pretty equivalent. I could not notice any performance differences. Since others seem to like the ROP (rugged offroad products) carb and have had good luck with it, that's the one I'll probably stick with.
Click to expand...
Thanks for the update! I'm glad the ROP worked out for you and you're happy with it.

I've seen those Amazon carbs before on Ebay. They're obviously not the correct carb because of the levers are very different. The hassle of making them work probably isn't worth it.
 
C

cfh

Well-Known Member
#23
#23
I decided to give the super cheap $8 Tecumseh carbs a try too. This one is advertised as good for HS50 motors, part number 632230 and 632272:
http://rover.ebay.com/rover/1/711-5...0001&campid=5335845805&icep_item=161896654182

I don't have a motor ready to try it yet, but i will keep this thread updated as that changes...

Just a general look at these el cheapo carbs... i like the choke lever. No spring drain on the float bowl.
tec_cheap2.jpg

tec_cheap1.jpg
 
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C

cfh

Well-Known Member
#24
#24
I installed the $8 ebay Tecumseh carbs into a pair of hs40 motors. These carbs seems to work just fine... no better or worse than the $15 models i highlighted above. I like the choke lever. It's on the correct (right) side of the carb, and it's a nice size and bend. No float bowl spring drain, but nearly none of the replacement carbs had that (i do miss that option.)

But there are two modification need for the $8 carb to really make it work.

First the side hole needs to be enlarged with a 1/16" drill bit. This is the same modification we did above to one of the $15 carbs (the one designed for the primer bulb, though this carb is not intended for use with a primer).

Second the throttle activator needs a 1/16" hole drilled into it. Otherwise there isn't a good position to hook up the lever from the governor to the carb. All the holes in that carb throttle activator are just in the wrong place to make the throttle operate smoothly.

After doing these two modifications, the $8 carb seems to work just fine. Again i could find no performance problem (or enhancements) with this carb. And at $8, it's hard to deny it!
 
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Orson_Yancey

Orson_Yancey

Member
#25
#25
CFH, Thanks for sharing this information. There was a time when I would disassemble and clean a
malfunctioning carb. But at $8 to $15 for a new carb, it is making more sense to put on a new carb.
Plus I plan to phase out the emissions (non-adjustable) carbs. I too like the spring drain on the
float bowl.
 
H

Havasu Dave

Moderator
#26
#26
Orson_Yancey said:
CFH, Thanks for sharing this information. There was a time when I would disassemble and clean a
malfunctioning carb. But at $8 to $15 for a new carb, it is making more sense to put on a new carb.
Plus I plan to phase out the emissions (non-adjustable) carbs. I too like the spring drain on the
float bowl.
Click to expand...
Some of us who have been using the cheap replacement carbs for a few years and running corn gas have had more problems with those carbs than the original Tecumseh carbs. Specifically, the float bowl shut off o ring, or perhaps the machining of the needle is such that they tend to flood.

The other problem is that all of these carbs run lean out of the box. Pilot jet settings tend to vary from either seated, or cracked, most likely again from inferior machining of the tapered needles. Your engines will run, but you don't get the fine tuning at idle you will get with an OEM carb.

Yes, out of the box, they seem like a great deal, $10 instead of $80. I am not alone in being done with them. Note that on a few occasions, upon receipt I have opened the bowl only to find one of the two bowl hinge holes were not cast properly resulting in only one hole holding the hinge rod.

Lowest possible quality at the lowest possible price.
 
C

cfh

Well-Known Member
#27
#27
i've put about 15 cheap carbs on motors and have not had a problem yet. In fact, i think i like the $8 version better than the $12-15 ones. I will say that the float bowl rubber ring was bad on one of the $15 models. But for some reason the $8 version seems to work out best. And you are right, they do run lean. but i haven't had any problems with that (nor any problems with adjustment.)

I think with any carb that is this inexpensive, a good inspection before installation is probably a good idea. like you mentioned, taking the bowl off to check things is probably a good idea. Again i haven't found any issues, but i'm sure, given the price, there will be some issue at some point.
 
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C

cfh

Well-Known Member
#28
#28
Here's a internal picture of the $8 carb. i don't see the issue with the casting on the float pin, at least on this particular carb. Overall the casting looks pretty good to me!

tec5.jpg
 
ZR9B

ZR9B

#29
#29
I just ordered the carb from rugged out doors....Its going on a 72 Hustler....now the only problem is why the aftermarket secondary wont line up....hmmm
 
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cfh

Well-Known Member
#30
#30
Tecumseh Carb Comparison on HS40 and HS50 engines - summary

after living with these inexpensive carbs on various bikes and HS40 and HS50 motors, i have to say, i like the $8 to $10 Tecumseh 632230 632272 replacement carb the best. The choke lever is more versatile (at least for my bikes.) And overall i would say the carb just seems to work a tiny bit better than the others. Overall performance is not that much different, *maybe* a tad more low end (but high end is the same.)

This picture sums it up nicely. The 632230 632272 carb $10 on the left, the more expensive $15 Rop 631921 carb on the right. See the difference? Not sure this really means much, but a bigger hole is better, right?

 
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C

cfh

Well-Known Member
#31
#31
I'm going to try and combine some misc threads into this one...

I've been playing with Dellorto carbs and Tecumseh HS50 motors. I bought a Rupp black widow, and it has the Dellorto ua19s. I rode the bike with a stock tecumseh carb, and the Dellorto is definitely a performance boast. Quite a nice bolt-on boast, but the price is rather high for those Ua19s carbs.

So i've been hunting around for other carbs, that would give a similar proformance boast, but not cost so much. I've been playing around with Mikuni style 16mm carbs. They are pretty cheap (about $15 on ebay, and work quite well on the HS50.) Essentially it's a Honda 80 carb.
https://www.ebay.com/itm/Carburetor...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649





I like this set up. By the way an inexpensive Db30 throttle ($12) works well with these slide carbs. The proformance does go up a bit with this set up. Mostly there's more throttle travel, and the high-end of the Tecumseh HS50 is improved.

But the problem is, they are too close to the engine and exhaust. So you have to make an aluminum extender. You can see that in the pics below. This gets the throttle cable away from the exhaust.







Again this is a nice and inexpensive modification (providing you can make the extender.) But these are only 16mm carbs. The Dellorto (which i'm using as a base, since it's performance is so nice), is 19mm. So how do we get to a bigger carb (without spending a lot of money)...
 
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C

cfh

Well-Known Member
#32
#32
Hunting around Ebay i found a Dellorto UB22s2 carb. This is 22mm, which is probably way too big, but the price was nice. And someone had already made a dellorto-to-tecumseh intake manifold, which came with the carb. So i bought it. Needed a couple small parts, but overall it was a nice modification and it looks cool as hell! Motor starts great with this carb too, first pull. Which is better than the ua19s motor (which usually takes a few pulls when the motor is cold.)



Definitely a performance improvement. I still like the Dellorto ua19s better, but it's so expensive and hard to find, it's not really an alternative.

 
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C

cfh

Well-Known Member
#33
#33
There was a India made dellorto 19mm clone on ebay for $25. I bought that, and frankly, it looks cool and would easily adapt to any minibike throttle. But the problem is, it has NO choke! for this reason i have not tried to make it work on a Tecumseh. Chokes are pretty damn important in my world (michigan). It's really too bad, but at 19mm, it's the ideal size. And at $25 it's the ideal price point too.
https://www.ebay.com/itm/New-Lambre...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649







 
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C

cfh

Well-Known Member
#34
#34
I've ordered a Mikuni clone 19mm carb. Have not received it yet, but should be here soon. That's the next thing to try. It may be the "sweet spot" in this carb experiment (finding low cost vs. performance). Again i'm using the Dellorto ua19s as my performance flat line. That's what i would like to hit (but without costing the money!) At $12, it's tough to not try one...
http://rover.ebay.com/rover/1/711-5...0001&campid=5335845805&icep_item=152671704586
 
C

cfh

Well-Known Member
#37
#37
I noticed that too on the Indian 19 mm clone. It’s not a mechanical choke like you would think. I can’t figure out how to hook a cable to it and what exactly it would even do.
 
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ole4

ole4

#38
#38
it works the same as the mikuni. There is an air passage from intake side (one of the little holes) to the back behind the slide and a plunger that blocks it off. When plunger is lifted it allows more air and fuel (there is a fuel pickup intersecting the air passage) into the engine to start. On the mikuni there is a lever operating the plunger on that india carb it needs a cable.
 
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